Simultaneous induction of HSP70 expression, and degranulation, in IgE/Ag-stimulated or extracellular HSP70-stimulated mast cells.

BACKGROUND: In mast cells, induction of HSP70 expression during antigen stimulation has not been reported. METHODS: Mouse bone marrow-derived mast cells (BMMC) were stimulated with IgE/Ag or HSP70. Induction of HSP70 expression and signaling protein phosphorylation were evaluated by immunoblotting. RESULTS: HSP70 expression is induced in BMMC at an early stage of IgE/Ag-dependent stimulation, some of which is released from the cells in a granule-associated form. Induction of HSP70 expression was also observed with an IgE/Ag-stimulated human basophilic cell line, indicating that the phenomenon is not restricted to mouse BMMC. The induction of HSP70 expression, and its release, followed a similar time course to that of degranulation. Released HSP70 seems to be responsible for degranulation and production of eicosanoids, at least in part, because a neutralizing anti-HSP70 antibody mitigated these activities and because exogenous HSP70 not only induced immediate degranulation followed by autocrine HSP70 expression but also enhanced degranulation in IgE/Ag-stimulated BMMC. Extracellular HSP70 was found to induce phosphorylation of linker for activation of T cells (LAT) and a series of downstream signaling molecules in BMMC. We further found that Fyn, Lyn, and spleen tyrosine kinase (Syk), which are known to concern LAT phosphorylation in IgE/Ag-stimulated BMMC, were not phosphorylated in HSP70-stimulated BMMC, whereas lymphocyte-specific protein tyrosine kinase (Lck) was phosphorylated. CONCLUSION: FcεRI stimulation in BMMC and basophils induces HSP70 expression and its release. Extracellular HSP70 induces degranulation and mediator release via phosphorylation of LAT.

Impact of an intervention programme on knowledge, attitudes and practices of population regarding severe fever with thrombocytopenia syndrome in endemic areas of Lu'an, China.

Knowledge, attitudes and practices (KAP) of the population regarding severe fever with thrombocytopenia syndrome (SFTS) in endemic areas of Lu'an in China were assessed before and after an intervention programme. The pre-intervention phase was conducted using a sample of 425 participants from the 12 selected villages with the highest rates of endemic SFTS infection. A predesigned interview questionnaire was used to assess KAP. Subsequently, an intervention programme was designed and applied in the selected villages. KAP was re-assessed for each population in the selected villages using the same interview questionnaire. Following 2 months of the programme, 339 participants had completed the re-assessed survey. The impact of the intervention programme was evaluated using suitable statistical methods. A significant increase in the KAP and total KAP scores was noted following the intervention programme, whereas the proportion of correct knowledge, the positive attitudes and the effective practices toward SFTS of respondents increased significantly. The intervention programme was effective in improving KAP level of SFTS in populations that were resident in endemic areas.

NecroX-5 suppresses IgE/Ag-stimulated anaphylaxis and mast cell activation by regulating the SHP-1-Syk signaling module.

BACKGROUND: IgE/Ag-stimulated mast cells release various pro-allergic inflammatory mediators, including histamine, eicosanoids, and pro-inflammatory cytokines. NecroX-5, a cell permeable necrosis inhibitor, showed cytoprotective effects in both in vitro and in vivo models. However, the anti-allergic effect of NecroX-5 has not yet been investigated. The aims of this study were to evaluate the anti-allergic activity of NecroX-5 in vivo and to investigate the underlying mechanism in vitro. METHODS: The anti-allergic activity of NecroX-5 was evaluated in vitro using bone marrow-derived mast cells (BMMCs) and IgE receptor-bearing RBL-2H3 or KU812 cells and in vivo using a mouse model of passive anaphylaxis. The levels of histamine, eicosanoids (PGD2 and LTC4 ), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were measured using enzyme immunoassay kits. The mechanism underlying the action of NecroX-5 was investigated using immunoblotting, immunoprecipitation, and gene knockdown techniques. RESULTS: NecroX-5 markedly inhibited mast cell degranulation and the synthesis of eicosanoids, TNF-α, and IL-6 by suppressing the activation of Syk, LAT, phospholipase Cγ1, MAP kinases, the Akt/NF-κB pathway, and intracellular Ca(2+) mobilization via the activation of phosphatase SHP-1. Oral administration of NecroX-5 effectively suppressed mast cell-dependent passive cutaneous and systemic anaphylactic reactions in a dose-dependent manner. CONCLUSIONS: NecroX-5 might be a potential candidate for the development of a novel anti-allergic agent that suppresses IgE-dependent mast cells signaling.

Betulinic acid enhances TGF-ß signaling by altering TGF-ß receptors partitioning between lipid-raft/caveolae and non-caveolae membrane microdomains in mink lung epithelial cells.

BACKGROUND: TGF-ß is a key modulator in the regulation of cell proliferation and migration, and is also involved in the process of cancer development and progression. Previous studies have indicated that TGF-ß responsiveness is determined by TGF-ß receptor partitioning between lipid raft/caveolae-mediated and clathrin-mediated endocytosis. Lipid raft/caveolae-mediated endocytosis facilitates TGF-ß degradation and thus suppressing TGF-ß responsiveness. By contrast, clathrin-mediated endocytosis results in Smad2/3-dependent endosomal signaling, thereby promoting TGF-ß responsiveness. Because betulinic acid shares a similar chemical structure with cholesterol and has been reported to insert into the plasma membrane, we speculate that betulinic acid changes the fluidity of the plasma membrane and modulates the signaling pathway associated with membrane microdomains. We propose that betulinic acid modulates TGF-ß responsiveness by changing the partitioning of TGF-ß receptor between lipid-raft/caveolae and non-caveolae microdomain on plasma membrane. METHODS: We employed sucrose-density gradient ultracentrifugation and confocal microscopy to determine membrane localization of TGF-ß receptors and used a luciferase assay to examine the effects of betulinic acid in TGF-ß-stimulated promoter activation. In addition, we perform western blotting to test TGF-ß-induced Smad2 phosphorylation and fibronectin production. RESULTS AND CONCLUSIONS: Betulinic acid induces translocation of TGF-ß receptors from lipid raft/caveolae to non-caveolae microdomains without changing total level of TGF-ß receptors. The betulinic acid-induced TGF-ß receptors translocation is rapid and correlate with the TGF-ß-induced PAI-1 reporter gene activation and growth inhibition in Mv1Lu cells.

[Inhibiting the pro-tumor and transcription factor FACT: Mechanisms].

Conventional antitumor therapy is often complicated by the emergence of the so-called cancer stem cells (CSCs), which are characterized by low metabolic rates and high resistance to almost all existing therapies. Many problems of clinical oncology and a poor efficacy of current treatments in particular are ascribed to CSCs. Therefore, it is important to develop new compounds capable of eliminating both rapidly proliferating tumor cells and standard treatment-resistant CSCs. Curaxins have been demonstrated to manifest various types of antitumor activity. Curaxins simultaneously affect at least three key molecular cascades involved in tumor development, including the p53, NF-κB, and HSF1 metabolic pathways. In addition, studies of some curaxins indicate that they can inhibit the transcriptional induction of the genes for matrix metalloproteinases 1 and 8 (MMP1 and MMP8); the PI3K/AKT/mTOR signaling cascades; cIAP-1 (apoptosis protein 1) inhibitor activity; topoisomerase II; and a number of oncogenes, such as c-MYC and others. In vivo experiments have shown that the CSC population increases on gemcitabine monotherapy and is reduced on treatment with curaxin CBL0137. The data support the prospective use of FACT inhibitors as new anticancer drugs with multiple effects on cell metabolism.

BCAS2 promotes prostate cancer cells proliferation by enhancing AR mRNA transcription and protein stability.

BACKGROUND: We showed previously that breast carcinoma amplified sequence 2 (BCAS2) functions as a negative regulator of p53. We also found that BCAS2 is a potential AR-associated protein. AR is essential for the growth and survival of prostate carcinoma. Therefore we characterised the correlation between BCAS2 and AR. METHODS: Protein interactions were examined by GST pull-down assay and co-immunoprecipitation. Clinical prostate cancer (PCa) specimens were evaluated by immunohistochemical assay. AR transcriptional activity and LNCaP cell growth were assessed by luciferase assay and MTT assay, respectively. RESULTS: BCAS2 expression was significantly increased in PCa. BCAS2 stabilised AR protein through both hormone-dependent and -independent manners. There are at least two mechanisms for BCAS2-mediated AR protein upregulation: One is p53-dependent. The p53 is suppressed by BCAS2 that results in increasing AR mRNA and protein expression. The other is via p53-independent inhibition of proteasome degradation. As BCAS2 can form a complex with AR and HSP90, it may function with HSP90 to stabilise AR protein from being degraded by proteasome. CONCLUSIONS: In this study, we show that BCAS2 is a novel AR-interacting protein and characterise the correlation between BCAS2 and PCa. Thus we propose that BCAS2 could be a diagnostic marker and therapeutic target for PCa.

Simultaneous presentation of acute disseminated encephalomyelitis (ADEM) and systemic lupus erythematosus (SLE) after enteroviral infection: can ADEM present as the first manifestation of SLE?

Central Nervous System (CNS) involvement of Systemic Lupus Erythematosus (SLE) includes a broad range of neuropsychiatric syndromes. Acute Disseminated Encephalomyelitis (ADEM) is a demyelinating CNS disorder characterized by encephalopathy and multifocal lesions predominantly involving the white matter on brain magnetic resonance imaging. ADEM associated with SLE has been only rarely reported. We report an unusual case of a 17-year-old girl who developed ADEM after enteroviral infection as the first manifestation of SLE. The authors emphasize that the patient's illness was preceded by enteroviral infection and that ADEM occurred before any other symptoms of SLE, which makes this case unique.

Restless legs syndrome is associated with cardio/cerebrovascular events and mortality in end-stage renal disease.

BACKGROUND AND PURPOSE: Earlier studies suggested an association between idiopathic restless legs syndrome (RLS) and cardiovascular diseases. However, the risk of cardiovascular events in patients with secondary RLS due to end-stage renal disease (ESRD) is unclear. Our aim was to examine whether ESRD patients with RLS had an increased risk of cardio/cerebrovascular events and mortality. METHODS: In all, 1093 ESRD patients were recruited between 2009 and 2010. The diagnosis and severity of RLS were assessed in a face-to-face interview. The occurrence of cardio/cerebrovascular events and death were confirmed by medical record review. The association between RLS and the outcomes of interest was examined using an adjusted multivariate Cox regression model. RESULTS: After a mean follow-up period of 3.7 ± 0.8 years, ESRD patients with RLS had a significantly higher risk of developing cardiovascular events and strokes [adjusted hazard ratio (aHR) 2.82, 95% confidence interval (CI) 2.02-4.11, and aHR 2.41, 95% CI 1.55-3.75, respectively] compared with patients without RLS. Increasing RLS severity was associated with an increasing likelihood of cardiovascular events [mild RLS severity, aHR 1.71 (95% CI 1.02-2.87); moderate, 2.79 (1.64-4.66); severe, 2.85 (1.99-4.46)] and strokes [mild, 1.89 (0.87-4.16); moderate, 2.42 (1.50-3.90); severe, 2.64 (1.49-4.91)] in a dose-dependent manner. RLS also increased the risk of total mortality in patients with ESRD [aHR 1.53 (95% CI 1.07-2.18), P = 0.02]; this association attenuated slightly after stratification by individual RLS severity category [mild RLS severity, aHR 1.44 (95% CI 0.78-2.67); moderate, 1.49 (0.98-2.55); severe, 2.03 (0.93-4.45)]. CONCLUSIONS: ESRD patients with RLS demonstrated an increased likelihood of cardio/cerebrovascular events and mortality.

A tryptophan metabolite, kynurenine, promotes mast cell activation through aryl hydrocarbon receptor.

BACKGROUND: Tryptophan metabolites have been suggested to play a role in immune modulation, wherein those have recently been shown to be endogenous ligands of aryl hydrocarbon receptor (AhR; a unique cellular chemical sensor). However, the involvement of tryptophan metabolites and AhR in modulating mast cell function remains to be fully defined. We therefore investigated that the functional impacts of tryptophan metabolites on human and mouse mast cell responses in vitro and their functional importance in vivo. METHODS: Three tryptophan metabolites, kynurenine (KYN), kynurenic acid (KA) and quinolinic acid (QA), were examined in terms of their effect on IgE-mediated responses in mouse bone marrow-derived mast cells (BMMCs) and in human peripheral blood-derived cultured mast cells (HCMCs) and on in vivo anaphylactic responses. For evaluation of AhR involvement, we examined the responses of mast cells from AhR-null or AhR-wild-type mice with the use of a known AhR antagonist, CH223191. RESULTS: Kynurenine, but not KA and QA, enhanced IgE-mediated responses, including degranulation, LTC4 release, and IL-13 production in BMMCs through the activation of PLCγ1, Akt, MAPK p38, and the increase of intracellular calcium. KYN also enhanced cutaneous anaphylaxis in vivo. These enhancing effects of KYN were not observed in AhR-deficient BMMCs and could be inhibited by CH223191 in BMMCs. Further, KYN had similar enhancing effects on HCMCs, which were inhibited by CH223191. CONCLUSION: The AhR-KYN axis is potentially important in modulating mast cell responses and represents an example of AhR's critical involvement in the regulation of allergic responses.

Association of candidate genetic variants with restless legs syndrome in end stage renal disease: a multicenter case-control study in Taiwan.

BACKGROUND AND PURPOSE: Recent genome-wide association studies have shown associations between multiple genetic variants and primary restless legs syndrome (RLS). Their roles in end stage renal disease (ESRD) related secondary RLS are not clear and studies in Asian populations are scarce. The association between candidate genetic variants and uremic RLS was investigated in a large cohort of Taiwanese dialysis patients. METHODS: Sixteen RLS-related genetic variants at six loci, including MEIS1, BTBD9, MAP2K5/SKOR1, PTPRD, TOX3/BC034767 and the intergenic region of chromosome 2p14, in a total of 993 ESRD patients (259 subjects with and 734 subjects without RLS) were genotyped using TaqMan genotyping assays. Multivariate logistic regression analysis was used to test for associations between the genotypes and RLS in ESRD. Power calculations were completed using the CATs Genetic Power Calculator with settings of a multiplicative genetic model. RESULTS: A modest association between the PTPRD variant rs4626664 and uremic RLS (odds ratio 1.52, 95% CI 1.03-2.23, P = 0.03) and a trend that TOX3/BC034767 variant rs3104767 may associate with the occurrence of RLS were observed in our dialysis population (odds ratio 1.74, 95% CI 0.97-3.11, P = 0.06). No associations between other genetic variants and risk and severity of RLS were observed in our ESRD cohort. CONCLUSIONS: The genetic variants of primary RLS candidate genes did not play a major role in our uremic RLS populations. The ethnic difference and heterogeneous etiologies underlying renal failure may partly explain the minor genetic contribution to uremic RLS in our populations. Further studies for other ethnicities will be of worth.

Restless legs syndrome in end-stage renal disease: a multicenter study in Taiwan.

BACKGROUND AND PURPOSE: Restless legs syndrome (RLS) is an underestimated movement disorder in patients with end-stage renal disease (ESRD). Several clinical and laboratory factors were inconsistently reported to associate with RLS. We aim to perform a large-scale multicenter study to investigate the possible associated risk factors of RLS in patients with ESRD in Taiwan, a country with the highest incidence of uremia in the world. METHODS: From October 2009 to October 2011, we constitutively recruited 1130 patients with ESRD from 17 hemodialysis centers. Demographic, laboratory data, presence and severity of RLS were collected. Odds ratios (ORs) were estimated by logistic regression models. RESULTS: We found the prevalence of RLS to be 25.3% in patients with ESRD. Having type 2 diabetes [OR = 3.61 (2.27-5.77), P < 0.01], low serum transferrin saturation [OR = 1.42 (1.01-2.03), P < 0.05] and duration of dialysis [OR = 1.09 (1.03-1.14), P < 0.01] were associated with RLS. In contrast, high serum hemoglobin level was inversely associated with RLS [OR = 0.61 (0.40-0.89), P < 0.05]. RLS has a significant impact on sleep quality in dialysis patients. Among patients with RLS, history of type 2 diabetes [OR = 4.04 (1.65-10.79), P < 0.05], low serum hemoglobin level [OR = 5.41 (2.43-13.12), P < 0.01] and duration of dialysis [OR = 1.01 (1.01-1.02), P < 0.01] were associated with increased severity of RLS. CONCLUSIONS: Our findings demonstrated that RLS is common in Taiwanese dialysis patients. Clinicians should have a high suspicion for the presence of RLS symptoms in patients with ESRD, especially those with type 2 diabetes, anemia, low serum iron status and long duration of dialysis.

Safety and efficacy of two-step peginterferon α-2a treatment in patients of chronic hepatitis B with acute exacerbation.

The focus of this study was to evaluate the safety and efficacy of sequential peginterferon α-2a (Pegasys) therapy for chronic hepatitis B with acute exacerbation [ALT > 10 × upper limit of normal (ULN), bilirubin <2.0 mg/dL]. Four groups of patients categorized by HBeAg status and treatment regimens were studied since May 2007. Nineteen HBeAg-positive patients (Group 1) had received entecavir  pretreatment  (when ALT > 10 × ULN) plus Pegasys (180 µg/kg/week, when ALT was 5-10 × ULN) for 24 weeks. Thirteen HBeAg-negative patients (Group 2) had the same protocol for 48 weeks. In both groups, entecavir was then discontinued 14 days after the initiation of Pegasys. The results were compared, respectively, to 35 HBeAg-positive patients (Group 3) and 24 HBeAg-negative patients (Group 4), all with ALT > 5 × ULN, under continual entecavir monotherapy. The ALT levels of patients in Group 1 and 2 who had received entecavir pretreatment for a duration of 19.63 ± 3.34 days were below four times of ULN following 4 weeks of Pegasys treatment. At week 96, the rates of sustained virological response were 69.2% (9/13) and 80% (8/10), and the relapse rates were 23.1% (3/13) and 11.2% (1/9) for HBeAg-positive and HBeAg-negative patients with two-step Pegasys treatment, respectively. The HBeAg seroconversion rates were 46.2% in Group 1, and 42.1% in Group 3; HBsAg loss rates were 15.4% (2/13) in Group 1, and 30% (3/10) in Group 2, whereas none achieved HBsAg loss with entecavir monotherapy (Group 3 and 4). The two-step Pegasys treatment offers an alternative, other than the nucleos(t)ides, for treating chronic hepatitis B with acute exacerbation and provides a safe, efficacious, short-term and finite strategy.

Prevalence of haematuria positively associated with urine albumin excretion in Type 2 diabetes.

AIMS: Some guidelines or studies consider haematuria an indication for renal biopsy or a potential cause of albuminuria that precludes accurate assessment of urinary albumin excretion. This study examined the justification of excluding haematuria in interpreting urinary albumin excretion in patients with Type 2 diabetes and its associations with other diabetes-related variables. METHODS: Between May and November 2008, patients with Type 2 diabetes at a single centre with data on urinary albumin excretion and urinalysis in the same urine sample were recruited. Urinary albumin excretion was determined by urine albumin/creatinine ratio in spot urine. Diagnosis of haematuria was made by positive urine occult blood from 1+ to 4+ and/or presence of more than nine red blood cells/ml in urinalysis. Demographic, anthropometric, clinical and laboratory variables and diabetes-associated complications were analysed. RESULTS: In total, 743 patients were enrolled. Prevalence of haematuria among patients with normoalbuminuria, microalbuminuria, or macroalbuminuria was 8.7% (n = 13), 16.1% (n = 67) and 35.8% (n = 64), respectively. Urine albumin/creatinine ratio was significantly higher, while macroalbuminuria was more common in patients with haematuria (n = 144) than in those without (n = 599). Multiple regression analysis identified urine albumin/creatinine ratio (odds ratio 1.33, P = 0.01) and macroalbuminuria (odds ratio 2.66, P = 0.01) as the only independent predictors of haematuria. Moreover, urine albumin/creatinine ratio was an independent predictor of haematuria in the macroalbuminuria subgroup (odds ratio 1.30, P = 0.04). CONCLUSIONS: Increased urine albumin/creatinine ratio and macroalbuminuria were the only independent predictors of haematuria in patients with Type 2 diabetes, raising questions on the justifications of excluding haematuria in interpreting urinary albumin excretion in patients with Type 2 diabetes and including haematuria as an indication for renal biopsy in those with macroalbuminuria.

Predicted risk of childhood allergy, asthma, and reported symptoms using measured phthalate exposure in dust and urine.

UNLABELLED: The associated risk of phthalate exposure, both parent compounds in the home and their metabolites in urine, to childhood allergic and respiratory morbidity, after adjusting for exposures of indoor pollutants, especially bioaerosols, was comprehensively assessed. Levels of five phthalates in settled dust from the homes of 101 children (3-9 years old) were measured, along with their corresponding urinary metabolites. Other environmental risk factors, including indoor CO2, PM2.5, formaldehyde, 1,3-ß-D-glucan, endotoxin, allergen and fungal levels, were concomitantly examined. Subject's health status was verified by pediatricians, and parents recorded observed daily symptoms of their children for the week that the home investigation visit took place. Significantly increased level of benzylbutyl phthalate, in settled dust, was associated with test case subjects (allergic or asthmatic children). Higher levels of dibutyl phthalate and its metabolites, mono-n-butyl phthalate, and mono-2-ethylhexyl phthalate were found to be the potential risk factors for the health outcomes of interest. Similarly, indoor fungal exposure remained a significant risk factor, especially for reported respiratory symptoms. The relative contribution from exposure to phthalates and indoor biocontaminants in childhood allergic and respiratory morbidity is, for the first time, quantitatively assessed and characterized. PRACTICAL IMPLICATIONS: For asthmatic and allergic children living in subtropical and highly developed environments like homes in Taiwan, controlling environmental exposure of phthalates may be viewed as equally important as avoiding indoor microbial burdens, for the management of allergy-related diseases. It is also recognized that multidisciplinary efforts will be critical in realizing the true underlying mechanisms associated with these observations.

Patterns of accentuated grey-white differentiation on diffusion-weighted imaging or the apparent diffusion coefficient maps in comatose survivors after global brain injury.

AIM: To determine what disease entities show accentuated grey-white differentiation of the cerebral hemisphere on diffusion-weighted images (DWI) or apparent diffusion coefficient (ADC) maps, and whether there is a correlation between the different patterns and the cause of the brain injury. METHODS AND MATERIALS: The DWI and ADC maps of 19 patients with global brain injury were reviewed and evaluated to investigate whether there was a correlation between the different patterns seen on the DWI and ADC maps and the cause of global brain injury. The ADC values were measured for quantitative analysis. RESULTS: There were three different patterns of ADC decrease: a predominant ADC decrease in only the cerebral cortex (n=8; pattern I); an ADC decrease in both the cerebral cortex and white matter (WM) and a predominant decrease in the WM (n=9; pattern II); and a predominant ADC decrease in only the WM (n=3; pattern III). CONCLUSION: Pattern I is cerebral cortical injury, suggesting cortical laminar necrosis in hypoxic brain injury. Pattern II is cerebral cortical and WM injury, frequently seen in brain death, while pattern 3 is mainly WM injury, especially found in hypoglycaemic brain injury. It is likely that pattern I is decorticate injury and pattern II is decerebrate injury in hypoxic ischaemic encephalopathy.Patterns I and II are found in severe hypoxic brain injury, and pattern II is frequently shown in brain death, whereas pattern III was found in severe hypoglycaemic injury.

Magnetic properties, phase evolution, and microstructure of melt spun Hf-substituted Sm(Co0.97Hf0.03)(x)Cy (x = 5-9; y = 0-0.1) nanocomposites.

Magnetic properties, phase evolution, and microstructure of melt spun Hf-substituted Sm(Co0.97Hf0.03)(x)Cy (x = 5-9; y = 0-0.1) ribbons quenched at the wheel speed of 40 m/s are investigated. X-ray diffraction analysis shows that the main phases existed in Sm(Co0.97Hf0.03)(x) ribbons are 1:5 phase for x = 5-5.5; 1:5 and 1:7 phases for x = 6; 1:7 phase for x = 6.5-7.5; 1:7 and 2:17 phases for x = 8; and only 2:17 phase for x = 8.5-9, respectively. For Sm(Co0.97Hf0.03)(x) (x = 5-9) ribbons, the optimum magnetic properties of B(r) = 5.6 kG, (i)H(c)= 15.6 kOe and (BH)(max) = 7.1 MGOe are obtained for Sm(Co0.97Hf0.03)6.5 ribbons. Furthermore, a slight amount of C addition in Sm(Co0.97Hf0.03)(x) ribbons slightly modify phase constitution and effectively refine the grain size from 200-700 nm for C free ribbons to 10-70 nm, strengthening the exchange coupling effect between magnetic grains of the ribbons. As a result, magnetic properties are further improved. The magnetic properties of B(r) = 6.9 kG, (i)H(c) = 9.2 kOe and (BH)(max) = 10.0 MGOe can be achieved for Sm(Co0.97Hf0.03)7.5C0.1 nanocomposites.

Magnetic properties of melt spun mischmetals-Fe-Ti-B nanocomposite ribbons.

Magnetic properties and phase evolution of melt spun R9.5Fe(bal.)Ti2B10 (R = MM(A), MM(B), MM(C), Pr, Nd, Ce, and La) nanocomposites have been investigated. Based on the results for the X-ray diffraction and thermal magnetic analysis, only 2:14:1 and alpha-Fe phases appear for R = MM(A) and Pr, and an additional Fe3B phase is present for R = MM(B), MM(C), Nd, and Ce. Besides, the uniform fine grain size of 20-40 nm is almost unchanged for the ribbons with various rare earth elements. Accordingly, magnetic properties of MM9.5Fe(bal.)Ti2B10 nanocomposites are mainly dominated by the composition of Mischmetals or the rare earth elements adopted, and are consistent with the outcome for the combinations of magnetic properties of their corresponding R9.5Fe(bal.)Ti2B10 nanocomposites. In this study, the optimum magnetic properties of B(r) = 9.3 kG, (i)H(c) = 12.1 kOe and (BH)(max) = 18.0 MGOe can be achieved for MM(B)9.5Fe(bal.)Ti2B10 nanocomposites. They not only exhibit comparable magnetic properties to the commercial available powders but also reduce the original material cost effectively.

Investigation of magnetic properties and microstructure of ultrathin Co films grown on Si(111)- 7 x 7 surface.

Magnetic properties and growth mechanism of ultrathin Co films on Si(111)-7 x 7 surface have been studied by using both surface magneto-optic Kerr effect (SMOKE) and scanning tunneling microscopy (STM), respectively. STM results show that the growth mechanism of ultrathin Co films on Si(111)-7 x 7 surface at room temperature belongs to Stranski-Krastanov (SK) growth mode. Due to formation of CoSi2 layer, no magnetic signal could be detected by SMOKE for 1-4 ML Co deposited on Si(111) surface. Because of rougher surface, both longitudinal and perpendicular magnetic anisotropy configuration appear for 4.2-10 ML Co/Si(111) films. When the Co thickness is increased to 10 ML, only longitudinal anisotropy configuration is found, resulting from the contribution to the volume anisotropy. Furthermore, in-plane coercivity increases with Co coverage because of enhancement of ferromagnetic coupling with Co thickness, out-of-plane coercivity increases with Co coverage due to the increment of demagnetized field, induced by the rougher Co surface and pinhole structures.

Effect of dopants on the soft magnetic properties and high frequency characteristics of FeCoBM (M = Ti, Nb, Hf, and Ta) thin films.

Effect of dopants on the soft magnetic properties and high frequency characteristics of FeCoBM thin films (M = Ti, Nb, Hf, and Ta) have been studied. For (Fe0.55Co0.45)(100-x)B(x) (x = 5-15) thin films, with the increase of B content, the resistivity was increased because B could decrease the crystallinity of the films. The (Fe0.55Co0.45)90B10 thin film showed the optimum properties, where 4piM(s) = 16.1 kG, H(ce) = 64.2 Oe, H(ch) = 13.5 Oe, H(k) = 310 Oe and p = 338 microomega-cm. To reduce the coercivity of the film, the elements M, including Ti, Nb, Hf, and Ta, were selected to substitute for B in the FeCoB films. It was found that (Fe0.55Co0.45)90B6Ti2Nb2 thin film after annealing at a temperature of 200 degrees C for 30 min showed the optimal properties, where 4piM(s) = 15.8 kG, H(ce) = 4.8 Oe, H(ch) = 3.6 Oe, H(k) = 224 Oe and p = 290 microomega-cm. The theoretically calculated ferromagnetic resonance frequency of the developed films can be higher than 5 GHz.

Co nanoislands on Au(111) and Cu(111) surfaces studied by scanning tunneling microscopy and spectroscopy.

Co nanoislands on the Au(111) and Cu(111) surfaces have been studied by scanning tunneling microscopy and spectroscopy. The experimental results showed that Co nanoislands prefer to aggregate at the step edge and dislocation sites on the reconstructed Au(111) surface and at the step edge on the Cu(111) surface, respectively. In addition, based on dZ/dV-V spectra, in both the Co/Au(111) and the Co/Cu(111) systems, Gundlach oscillation was observed. From the peak shift of dZ/dV-V spectra between Co nanoisland and substrate surface, we can quantitatively obtain that the constant energy separation is -0.13 +/- 0.01 eV for the Co/Au(111) system, and 0.41 +/- 0.02 eV for the Co/Cu(111) system, respectively. These values indicate the work function difference between Co nanoisland and these surfaces.