Hafnium silicide formation on Si(100) upon annealing

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORHigh dielectric constant materials, such as HfO2, have been extensively studied as alternatives to SiO2 in new generations of Si based devices. Hf silicate/silicide formation has been reported in almost all literature studies of Hf based oxides on Si, using different methods of preparation. A silicate interface resembles close to the traditional Si/SiO2. The silicate very likely forms a very sharp interface between the Si substrate and the metal oxide, and would be suitable for device applications. However, the thermal instability of the interfacial silicate/oxide film leads to silicidation, causing a dramatic loss of the gate oxide integrity. Despite the importance of the Hf silicide surface and interface with Si, only a few studies of this surface are present in the literature, and a structural determination of the surface has not been reported. This paper reports a study of the Hf silicide formation upon annealing by using a combination of XPS, LEED, and x-ray photoelectron diffraction (XPD) analyses. Our results clearly indicate the formation of a unique ordered Hf silicide phase (HfSi2), which starts to crystallize when the annealing temperature is higher than 550 °C.High dielectric constant materials, such as HfO2, have been extensively studied as alternatives to SiO2 in new generations of Si based devices. Hf silicate/silicide formation has been reported in almost all literature studies of Hf based oxides on Si, using different methods of preparation. A silicate interface resembles close to the traditional Si/SiO2. The silicate very likely forms a very sharp interface between the Si substrate and the metal oxide, and would be suitable for device applications. However, the thermal instability of the interfacial silicate/oxide film leads to silicidation, causing a dramatic loss of the gate oxide integrity. Despite the importance of the Hf silicide surface and interface with Si, only a few studies of this surface are present in the literature, and a structural determination of the surface has not been reported. This paper reports a study of the Hf silicide formation upon annealing by using a combination of XPS, LEED, and x-ray photoelectron diffraction (XPD) analyses. Our results clearly indicate the formation of a unique ordered Hf silicide phase (HfSi2), which starts to crystallize when the annealing temperature is higher than 550 °C.747110FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORSem informaçãoSem informação170/04This work was financially supported by DAAD (PROBRAL D/03/23553) from Germany, and FAPESP, CNPq, and CAPES (PROBRAL 170/04) from Brazil. A.S. especially would like to thank CAPES for their support

Epicardial adipose tissue in patients with heart failure

<p>Abstract</p> <p>Purpose</p> <p>The aim of this study was to evaluate the extent of epicardial adipose tissue (EAT) and its relationship with left ventricular (LV) parameters assessed by cardiovascular magnetic resonance (CMR) in patients with congestive heart failure (CHF) and healthy controls.</p> <p>Background</p> <p>EAT is the true visceral fat deposited around the heart which generates various bioactive molecules. Previous studies found that EAT is related to left ventricular mass (LVM) in healthy subjects. Further studies showed a constant EAT to myocardial mass ratio in normal, ischemic and hypertrophied hearts.</p> <p>Methods</p> <p>CMR was performed in 66 patients with CHF due to ischemic cardiomyopathy (ICM), or dilated cardiomyopathy (DCM) and 32 healthy controls. Ventricular volumes, dimensions and LV function were assessed. The amount of EAT was determined volumetrically and expressed as mass indexed to body surface area. Additionally, the EAT/LVM and the EAT/left ventricular remodelling index (LVRI) ratios were calculated.</p> <p>Results</p> <p>Patients with CHF had less indexed EAT mass than controls (22 ± 5 g/m²versus 34 ± 4 g/m², p < 0.0001). In the subgroup analysis there were no significant differences in indexed EAT mass between patients with ICM and DCM (21 ± 4 g/m²versus 23 ± 6 g/m², p = 0.14). Linear regression analysis showed that with increasing LV end-diastolic diameter (LV-EDD) (r = 0.42, p = 0.0004) and LV end-diastolic mass (LV-EDM) (r = 0.59, p < 0.0001), there was a significantly increased amount of EAT in patients with CHF. However, the ratio of EAT mass/LV-EDM was significantly reduced in patients with CHF compared to healthy controls (0.54 ± 0.1 versus 0.21 ± 0.1, p < 0.0001). In CHF patients higher indexed EAT/LVRI-ratios in CHF patients correlated best with a reduced LV-EF (r = 0.49, p < 0.0001).</p> <p>Conclusion</p> <p>Patients with CHF revealed significantly reduced amounts of EAT. An increase in LVM is significantly related to an increase in EAT in both patients with CHF and controls. However, different from previous reports the EAT/LVEDM-ratio in patients with CHF was significantly reduced compared to healthy controls. Furthermore, the LV function correlated best with the indexed EAT/LVRI ratio in CHF patients. Metabolic abnormalities and/or anatomic alterations due to disturbed cardiac function and geometry seem to play a key role and are a possible explanation for these findings.</p

Structure determination of three-dimensional hafnium silicide nano structures on Si(1 0 0) by means of X-ray photoelectron diffraction

DAAD - DEUTSCHER AKADEMISCHER AUSTAUSCHDIENSTCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORDFG - DEUTSCHE FORSCHUNGSGEMEINSCHAFTWe propose a modified zirconium silicide model for the structure of HfSi2 islands on Si(1 0 0). We studied this system in a combined investigation by means of photoelectron diffraction (XPD), photoelectron spectroscopy and atomic force microscopy. Synchrotron radiation was used for enhanced energy resolution and surface sensitivity. Calculated XPD patterns of model clusters reflecting the structure as well as the morphology of the islands exhibit an excellent agreement with the experimental results. From LEED and AFM measurements a preferential nano structure growth along the [0 1 1] and [0 1 1] direction was observed. Complementary XPD results clearly show that the HfSi2 structures are silicon terminated.6022436473653DAAD - DEUTSCHER AKADEMISCHER AUSTAUSCHDIENSTCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORDFG - DEUTSCHE FORSCHUNGSGEMEINSCHAFTDAAD - DEUTSCHER AKADEMISCHER AUSTAUSCHDIENSTCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORDFG - DEUTSCHE FORSCHUNGSGEMEINSCHAFTDAAD [415-BR-PROBRAL-D-03-23553]CAPES [PROBRAL 170/04]DFG [1649/7-1]415-BR-PROBRAL-D-03-23553PROBRAL 170/041649/7-

Macrophages in T cell/histiocyte rich large B cell lymphoma strongly express metal-binding proteins and show a bi-activated phenotype.

Abundant macrophage infiltration in tumors often correlates with a poor prognosis. T cell/histiocyte rich large B cell lymphoma (THRLBCL) is a distinct aggressive B cell lymphoma entity showing a high macrophage content. To further elucidate the role of tumor-associated macrophages in THRLBCL, we performed gene expression profiling of microdissected histiocyte subsets of THRLBCL, nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), Piringer lymphadenitis, sarcoidosis, nonspecific lymphadenitis and monocytes from peripheral blood. In a supervised principal component analysis, histiocytes from THRLBCL were most closely related to epithelioid cells from NLPHL, with both types of cells expressing genes related to proinflammatory and regulatory macrophage activity. Moreover, histiocytes from THRLBCL strongly expressed metal-binding proteins like MT2A, by which histiocytes of THRLBCL can be distinguished from the other histiocyte subsets investigated. Interestingly, the validation at the protein level showed a strong expression of TXN, CXCL9, MT2A and SOD2 not only in macrophages of THRLBCL but also in the tumor cells of NLPHL and classical Hodgkin lymphoma (cHL). Overall, the present findings indicate that macrophages in the microenvironment of THRLBCL have acquired a distinct gene expression pattern that is characterized by a mixed M1/M2 phenotype and a strong expression of several metal binding proteins. The microenvironments in NLPHL and THRLBCL appear to have a similar influence on the macrophage phenotype. The high expression of metal binding proteins in histiocytes of THRLBCL may be diagnostically useful, but a potential pathophysiological role remains to be identified.status: publishe

Magnetic Resonance Imaging of the Epicardial Adipose Tissue

Epicardial adipose tissue (EAT) is a measurable risk factor and marker of visceral adipose tissue. Magnetic resonance imaging (MRI) is considered the gold standard technique to measure the adipose tissue, also because it does not require ionizing radiations. Dedicated cardiac magnetic resonance (CMR) imaging protocols have been developed to assess EAT volume. CMR provides a precise and noninvasive assessment of both EAT thickness and volume. As EAT is not equally distributed through the heart and when abundant may fill in folding spaces, steady-state free precession (SSFP) sequences of CMR should be used to more accurately measure the different and deeper EAT locations. Proton magnetic resonance spectroscopy (1H-MRS) is the gold standard technique to measure myocardial triglyceride content that is independently correlated with ultrasound measured EAT thickness