Role of nucleation sites on the formation of nanoporous Ge

The role of nucleation sites on the formation of nanoporousGe was investigated. Three Gefilms with different spherical or columnar pore morphologies to act as inherent nucleation sites were sputtered on (001) Ge. Samples were implanted 90° from incidence at 300 keV with fluences ranging from 3.0 × 10¹⁵ to 3.0 × 10¹⁶Ge⁺/cm². Electron microscopy investigations revealed varying thresholds for nanoporousGe formation and exhibited a stark difference in the evolution of the Ge layers based on the microstructure of the initial film. The results suggest that the presence of inherent nucleation sites significantly alters the onset and evolution of nanoporousGe.The authors acknowledge the Intel Corporation for funding this work

Vital Tooth Whitening Effects on Oral Health-Related Quality of Life in Older Adults

Purpose: The purpose of this study was to determine if vital tooth whitening affects oral health-related quality of life (OHRQOL) in adults age 50 years and older, and if tooth whitening causes increased participation in social activities. Methods: Using a 2 group, single blind, randomized, pre-test, multiple post-test design, 62 participants were enrolled. The experimental group used a whitening product twice daily for 3 weeks. The control group used no whitening products. The Oral Health Impact Profile (OHIP) served as the pre- and post-test measure. The OHIP measures OHRQOL on 7 subscales: functional factors, psychological disabilities, psychological discomforts, physical disabilities, social disabilities, handicaps and physical pain. Additional questions measured the subjects\u27 social activities at baseline, 3 weeks and 3 months. Data from 53 participants, who completed the study, were analyzed using paired t-tests and ANOVA at p=0.05. Results: Statistical significance was observed for the OHIP physical pain subscale (p=0.0029) and the handicap subscale (p=0.05). Pre- to post-test means of the physical pain subscale increased in the experimental group (4.84 to 7.10), suggesting a lower OHRQOL, most likely related to tooth sensitivity experienced by the experimental group. Means from pre- to post-test of the handicap subscale (1.96 to 1.19) reveal that the experimental group reported an improved OHRQOL and felt they were more willing to work. Repeated measures ANOVA and Tukey\u27s post-hoc tests revealed that the experimental group reported significantly less (p=0.04) social activities at the 3 month post-test (3.92 to 3.45). No statistically significant between-group differences were observed in the overall OHIP score for functional factors, psychological disabilities, psychological discomforts, physical disabilities and social disabilities. Conclusion: Results indicate that vital tooth whitening does not improve overall OHRQOL in older adults

Substrate orientation dependence on the solid phase epitaxial growth rate of Ge

The solid phase epitaxial growth process has been studied at 330 °C by transmission electron microscopy for Ge wafers polished at 10°–15° increments from the [001] to [011] orientations. The velocity showed a strong dependence on substrate orientation with the [001] direction displaying a velocity 16 times greater than the [111] direction. A lattice kinetic Monte Carlo model was used to simulate solid phase epitaxial growth (SPEG) rates at different orientations, and simulations compared well with experimental results. Cross sectional transmission electron microscopy and plan view transmission electron microscopy revealed stacking fault and twin defect formation in the [111] orientation where all other orientations showed only hairpin dislocations. The twin defects formed from Ge SPEG were comparatively less dense than what has previously been reported for Si, which gave rise to higher normalized velocities and a constant [111] SPEG velocity for Ge.The authors acknowledge Intel Corporation for funding this work. I.M.-B. acknowledges funding from the European project MASTIC (PCIG09-GA-2011-293783)

Nanostructured ion beam-modified Ge films for high capacity Li ion battery anodes

Nanostructured ion beam-modified Geelectrodes fabricated directly on Ni current collector substrates were found to exhibit excellent specific capacities during electrochemical cycling in half-cell configuration with Li metal for a wide range of cycling rates. Structural characterization revealed that the nanostructured electrodes lose porosity during cycling but maintain excellent electrical contact with the metallic current collector substrate. These results suggest that nanostructured Geelectrodes have great promise for use as high performance Li ion battery anodes

Low-energy Coulomb excitation of 62^{62}Fe and 62^{62}Mn following in-beam decay of 62^{62}Mn

Sub-barrier Coulomb-excitation was performed on a mixed beam of $^{62}$Mn and $^{62}$Fe, following in-trap $\beta^{-}$ decay of $^{62}$Mn at REX-ISOLDE, CERN. The trapping and charge breeding times were varied in order to alter the composition of the beam, which was measured by means of an ionisation chamber at the zero-angle position of the Miniball array. A new transition was observed at 418~keV, which has been tentatively associated to a $(2^{+},3^{+})\rightarrow1^{+}_{g.s.}$ transition. This fixes the relative positions of the $\beta$-decaying $4^{+}$ and $1^{+}$ states in $^{62}$Mn for the first time. Population of the $2^{+}_{1}$ state was observed in $^{62}$Fe and the cross-section determined by normalisation to the $^{109}$Ag target excitation, confirming the $B(E2)$ value measured in recoil-distance lifetime experiments.Comment: 9 pages, 10 figure

Safety of spallation sources in the accelerator production of tritium

The Accelerator Production of Tritium (APT) project will employ a high power proton accelerator to generate neutrons in a spallation target for the production of tritium. This paper will describe major attributes of the safety of this facility. 1 fig

Assessment of Exploration Exercise Concepts and Operations Methodology in a BAA Habitat Test Environment

No abstract availabl

First observation of excited states in 173Hg

The neutron-deficient nucleus 173Hg has been studied following fusion-evaporation reactions. The observation of gamma rays decaying from excited states are reported for the first time and a tentative level scheme is proposed. The proposed level scheme is discussed within the context of the systematics of neighbouring neutron-deficient Hg nuclei. In addition to the gamma-ray spectroscopy, the alpha decay of this nucleus has been measured yielding superior precision to earlier measurements.Comment: 5 pages, 4 figure

A De Novo Expression Profiling of Anopheles funestus, Malaria Vector in Africa, Using 454 Pyrosequencing

BACKGROUND: Anopheles funestus is one of the major malaria vectors in Africa and yet there are few genomic tools available for this species compared to An. gambiae. To start to close this knowledge gap, we sequenced the An. funestus transcriptome using cDNA libraries developed from a pyrethroid resistant laboratory strain and a pyrethroid susceptible field strain from Mali. RESULTS: Using a pool of life stages (pupae, larvae, adults: females and males) for each strain, 454 sequencing generated 375,619 reads (average length of 182 bp). De novo assembly generated 18,103 contigs with average length of 253 bp. The average depth of coverage of these contigs was 8.3. In total 20.8% of all reads were novel when compared to reference databases. The sequencing of the field strain generated 204,758 reads compared to 170,861 from the insecticide resistant laboratory strain. The contigs most differentially represented in the resistant strain belong to the P450 gene family and cuticular genes which correlates with previous studies implicating both of these gene families in pyrethroid resistance. qPCR carried out on six contigs indicates that these ESTs could be suitable for gene expression studies such as microarray. 31,000 sites were estimated to contain Single Nucleotide Polymorphisms (SNPs) and analysis of SNPs from 20 contigs suggested that most of these SNPs are likely to be true SNPs. Gene conservation analysis confirmed the close phylogenetic relationship between An. funestus and An. gambiae. CONCLUSION: This study represents a significant advance for the genetics and genomics of An. funestus since it provides an extensive set of both Expressed Sequence Tags (ESTs) and SNPs which can be readily adopted for the design of new genomic tools such as microarray or SNP platforms