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Abstract: This report discusses the structural and spectroscopic analysis of yttria-stabilized-zirconia (YSZ) thin films grown on Al2O3(0001) substrates. It is found that the changes of oxygen partial pressure during the growth are closely related to the surface chemical compositions and the surface crystal orientations of the thin films. The presence of oxygen partial pressure produces a polycrystalline structure on the thin film while a preferred orientation of crystal structures is formed under no oxygen partial pressure. Difficulty arises in identifying the structure of the thin films due to the broad characteristics of the x-ray diffraction (XRD) peaks; however, the XRD rocking scan suggests the existence of two lateral domain sizes. The chemical analysis of the thin films from x-ray photoelectron spectroscopy measurements indicates the enrichment of surface yttrium-oxide as the oxygen partial pressure increases. The detailed analysis of valence band spectra also suggests that the thin films undergo a surface structural phase transition, i.e., transforming from a single tetragonal structure to a mixed (cubic+monoclinic) structure. Furthermore, the optical data display the small increments of the band gap as the oxygen partial pressure increases, which reflects the presence of the structural phase transition of the thin films. [Copyright &y& Elsevier]

The increased growth in the use of tip-based sensing, manipulations, and fabrication of devices in atomic force microscopy (AFM) necessitates the accurate prediction of the dynamic behavior of the AFM probe. The chip holder, to which the micro-sensing device is attached, and the rest of the AFM system can affect the overall dynamics of the probe. In order to consider these boundary effects, we propose a novel receptance coupling method to mathematically combine the dynamics of the AFM setup and probe, based on the equilibrium and compatibility conditions at the joint. Once the frequency response functions of displacement over force at the tool tip are obtained, the dynamic interaction forces between the tip and the sample in nanoscale can be determined by measuring the probe tip displacement. [ABSTRACT FROM AUTHOR]

Objectives The use of umbilical cord blood (CB) that is genetically resistant to HIV infection has been proposed as a novel stem cell therapy for the treatment of patients with AIDS. These genetically unique CB units (CBUs) should be present in public CB banks at a predicted frequency. Methods The chemokine (C-C motif) receptor 5 ( CCR5) genotypes of CBUs donated to the M. D. Anderson CB Bank by four Houston area hospitals were determined by polymerase chain reaction (PCR) and DNA sequencing. Results The frequency of CCR5Δ32/ Δ32 CBUs was consistent with the frequency of the CCR5Δ32 allele in human populations, and was apparently dependent on the ethnic population of the parents of the newborns from whom the CBUs were collected. Conclusions Routine genotyping to identify HIV-resistant CBUs could create a bank of CB-derived stem/progenitor cells with which to treat HIV infection. [ABSTRACT FROM AUTHOR]

Silent brain infarctions (SBIs), leukoaraiosis (LA), and microbleeds (MBs) are ischaemic silent radiologic abnormalities that act as predictors of subsequent strokes. This study investigated the independent effect of silent radiologic abnormalities on initial stroke severity and short-term outcome. A consecutive series of patients who had their first ischaemic stroke within 72 h of symptom onset were included. Demographic and clinical characteristics were collected on admission, and magnetic resonance imaging was performed to evaluate the ischaemic lesion, SBI, LA, and MB. Factors potentially associated with lower initial stroke severity (admission NIH Stroke Scale 0-5) and good short-term outcome (discharge NIH Stroke Scale 0-5, modified Rankin Scale 0-1) were validated by multivariate analysis. Silent brain infarctions were noted in 82 (45%) of the 182 patients. Although there were no statistically significant differences in stroke subtypes and lesion location, univariate analysis revealed that patients with SBI had reduced stroke severity ( P = 0.005) and infarction volume ( P = 0.001). After adjusting for covariates, the presence of SBI was independently associated with lower stroke severity and good short-term outcome when the NIH Stroke Scale was used as dependent variable (OR 3.368, 95% CI 1.361-8.332, P = 0.009; OR 3.459, 95% CI 1.227-9.755, P = 0.019, respectively). However, the presence of SBI lost significance when the discharge-modified Rankin Scale was used as dependent variable ( P = 0.058). Amongst silent radiologic abnormalities, SBI was the only predictor of reduced stroke severity and infarct volume. Silent brain infarction deserves more attention in evaluating stroke severity. [ABSTRACT FROM AUTHOR]