With an ever-expanding demand for data storage, transducers, and microelectromechanical (MEMS) systems applications, materials with superior ferroelectric and piezoelectric responses are of great interest. The lead zirconate titanate (PZT) family of materials has served as the cornerstone for such applications up until now. A critical drawback of this material, however, is the presence of lead and the recent concerns about the toxicity of lead-containing devices. Recently, the lead-free ferroelectric BiFeO 3 (BFO) has attracted a great deal of attention because of its superior thin-film ferroelectric properties, [1,2] which are comparable to those of the tetragonal, Ti-rich PZT system; therefore, BFO provides an alternate choice as a "green" ferro/piezoelectric material. Another advantage of BFO is its high ferroelectric Curie temperature (T c = 850°C in single crystals), [3,4] which enables it to be used reliably at high temperatures. The ferroelectric domain structure of epitaxial BFO films are typically discussed in the context of the crystallographic model of Kubel and Schmid; [5] however, by suppressing other structural variants in BFO, we can obtain periodic domain structures that may open additional application opportunities for this material. Ferroelectrics with periodic domain structures are of great interest for applications in photonic devices [6] and nanolithography.[7] Such a periodic polarization could be obtained by applying an external electric field while utilizing lithographically defined electrodes or by a direct writing process. [8,9] To obtain sub-micrometer feature sizes, however, domain engineering using a scanning force microscope with an appropriate bias voltage must be used to fabricate the patterned domain structures.[10] Unfortunately, this method works only on small areas and is limited by its slow scanning rate. Theoretical models predict the feasibility of controlling the domain architecture in thin films through suitable control over the heteroepitaxial constraints. [11] In the case of BFO thin films, we have found that such a control is indeed possible, mainly through control over the growth of the underlying SrRuO 3 electrode. Using this approach, we demonstrate the growth of highly ordered 1D ferroelectric domains in 120 nm thick BFO films. On the (001) C perovskite surface there are eight possible ferroelectric polarization directions corresponding to four structural variants of the rhombohedral ferroelectric thin film. (For simplicity, the c and o subscripts refer to the pseudocubic structures for BFO and orthorhombic structures of SrRuO 3 (SRO) and DyScO 3 (110) O (DSO), respectively.) Domain patterns can develop with either {100} C or {101} C boundaries for (001) C -oriented rhombohedral films. [12] In both cases, the individual domains in the patterns are energetically degenerate and thus equal-width stripe patterns are theoretically predicted. When the spontaneous polarization is included in the analysis, the {100} C boundary patterns have no normal component of the net po...

The valence-band offset has been determined to be 3.83± 0.05 eV at the atomic-layer-deposition Al 2 O 3 / InGaAs interface by x-ray photoelectron spectroscopy. The Au-Al 2 O 3 / InGaAs metal-oxide-semiconductor diode exhibits current-voltage characteristics dominated by Fowler-Nordheim tunneling. From the current-voltage data at forward and reverse biases, a conduction-band offset of 1.6± 0.1 eV at the Al 2 O 3-InGaAs interface and an electron effective mass ϳ0.28± 0.04m 0 of the Al 2 O 3 layer have been extracted. Consequently, combining the valence-band offset, the conduction-band offset, and the energy-band gap of the InGaAs, the energy-band gap of the atomic-layer-deposited Al 2 O 3 is 6.65± 0.11 eV.

Traditionally, platelets have been thought to contribute to the induction and propagation of infective endocarditis (IE). However, recent studies suggest that platelets may potentially mitigate IE via secretion of a-granule-derived platelet microbicidal protein (PMP). In this study, we compared the PMP susceptibility of bacteremic isolates from patients with and without IE. Isolates of Staphylococcus aureus (n = 17), coagulasenegative staphylococci (CNS; n = 28), viridans streptococci (VS; n = 54), and Enterococcus faecalis (n = 20), each at a final inoculum of 2 x 103 CFU/ml, were exposed to PMP [100 U/ml, (5 ,ug/ml)] for 2 h, and the percent survival was determined. For S. aureus, CNS, and VS isolates, there was a significant correlation between an IE source and increased percent survival post-PMP exposure; the mean percent survivals of S.aureus, CNS, and VS were significantly greater for IE versus non-IE isolates (P < 0.005 for each organism). No significant correlation was observed between the source of bacteremic E. faecalis isolates and PMP susceptibility. These data suggest that staphylococcal and VS (but not enterococcal) resistance to PMP may facilitate either the induction or progression of IE.

BackgroundThis study is to investigate the significance and risk factors of fecal toxigenic (tCdC) or non-toxigenic Clostridium difficile colonization (ntCdC) among hospitalized patients.MethodsAdults admitted to medical wards in a district hospital between January 2011 and June 2012 were enrolled, and those with a history of colectomy, C. difficile fecal colonization or infection or receipt of either metronidazole or oral vancomycin within 3 months, were excluded. Stools collected within 48 hours after admission and every week during hospitalization were cultured for C. difficile.FindingsAmong the 441 enrolled patients, 84 (20.0%) had CdC at initial screening, including 58 (13.2%) with tCdC and 26 (6.8%) with ntCdC. Among patients with initial negative fecal screening for CdC, it took an average of 70.6 days or 66.5 days to develop tCdC or ntCdC during the study period. Finally 78 (17.7%) had tCdC and 34 (7.7%) had ntCdC. During the follow-up period, the patients with tCdC had a higher risk of CDAD (11/79, 14.1%) than those without CdC (3/328, 0.9%) and those with ntCdC (0/34, 0%) (P<0.001). In multivariate analysis, the TLR4 rs1927914 polymorphism (GG genotype) (odds ratio [OR] 4.4, 95% confidence interval [CI] 1.6–11.8, P = 0.003) and recent cefepime therapy (OR 5.3, 95% CI 2.1–13.2, P<0.001) were independently associated with tCdC, whereas recent cefuroxime (OR 11.7, 95% CI 2.3–60.2, P = 0.003) and glycopeptide therapy (OR 10.9, CI: 2.1–57.2, P = 0.005) associated with ntCdC.ConclusionThe incidence of CDAD is highest in patients with tCdC and lowest in patients with ntCdC, and the TLR4 rs1927914 polymorphism GG genotype and recent cefepime therapy were independently associated with tCdC.

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