566 research outputs found
Longitudinal Eigenvibration of Multilayer Colloidal Crystals and the Effect of Nanoscale Contact Bridges
Longitudinal contact-based vibrations of colloidal crystals with a controlled
layer thickness are studied. These crystals consist of 390 nm diameter
polystyrene spheres arranged into close packed, ordered lattices with a
thickness of one to twelve layers. Using laser ultrasonics, eigenmodes of the
crystals that have out-of-plane motion are excited. The particle-substrate and
effective interlayer contact stiffnesses in the colloidal crystals are
extracted using a discrete, coupled oscillator model. Extracted stiffnesses are
correlated with scanning electron microscope images of the contacts and atomic
force microscope characterization of the substrate surface topography after
removal of the spheres. Solid bridges of nanometric thickness are found to
drastically alter the stiffness of the contacts, and their presence is found to
be dependent on the self-assembly process. Measurements of the eigenmode
quality factors suggest that energy leakage into the substrate plays a role for
low frequency modes but is overcome by disorder- or material-induced losses at
higher frequencies. These findings help further the understanding of the
contact mechanics, and the effects of disorder in three-dimensional micro- and
nano-particulate systems, and open new avenues to engineer new types of micro-
and nanostructured materials with wave tailoring functionalities via control of
the adhesive contact properties
Final Science Reports of the US Experiments Flown on the Russian Biosatellite Cosmos 2229
Cosmos 2229 was launched on December 29, 1992, containing a biological payload including two young male rhesus monkeys, insects, amphibians, and cell cultures. The biosatellite was launched from the Plesetsk Cosmodrome in Russia for a mission duration of 11.5 days. The major research objectives were: (1) Study of adaptive response mechanisms of mammals during flight; and (2) Study of physiological mechanisms underlying vestibular, motor system and brain function in primates during early and later adaptation phases. American scientists and their Russian collaborators conducted 11 experiments on this mission which included extensive preflight and postflight studies with rhesus monkeys. Biosamples and data were subsequently transferred to the United States. The U.S. responsibilities for this flight included the development of experiment protocols, the fabrication of some flight instrumentation and experiment-specific ground-based hardware, the conducting of preflight and postflight testing and the analysis of biospecimens and data for the U.S. experiments. A description of the Cosmos 2229 mission is presented in this report including preflight, on-orbit and postflight activities. The flight and ground-based bioinstrumentation which was developed by the U.S. and Russia is also described, along with the associated preflight testing ot the U.S. hardware. Final Science Reports for the experiments are also included
m7824 msb0011359c a bifunctional fusion protein targeting pd l1 and tgf β in patients with post platinum esophageal adenocarcinoma eac preliminary results from a phase i cohort
n/
The cognitive-spiritual dimension - an important addition to the assessment of quality of life: Validation of a questionnaire (SELT-M) in patients with advanced cancer
Questions of meaning and challenge by illness, i.e., the spiritual dimension of quality of life (QL) traditionally played an important role in anthroposophically oriented medicine and have gained importance in palliative medicine and supportive care. In the context of a research project on QL in patients with advanced cancer, we therefore investigated the psychometric properties of a questionnaire covering spiritual QL issues, with the aim of providing a module for the assessment of cognitive-spiritual QL. Patients and methods: We investigated 89 patients with advanced breast and gastro-intestinal cancer. Construct validity of a modified version of the SELT (Skalen zur Erfassung von Lebensqualitat bei Tumorkranken), the SELT-M was tested by multitrait scaling analysis. Discriminant and convergent validity were also tested. The EORTC QLQ-C30 was used as a standard for validation. Results showed the SELT-M as feasible in administration. Four of the five SELT-M subscales were internally consistent (Cronbach's Alpha = ≥0.7). The subscale on spiritual QL showed higher within than outside subscale correlations for six of its eight items. Association of the SELT-M with the EORTC QLQ-C30 was good for the items and subscales covering the same aspects of QL in both questionnaires: emotional (Spearman r = 0.61), physical functioning (r= −0.54) and fatigue (r= −0.75). In accordance with expectations, there was no association between spiritual QL with any EORTC QLQ-C30 subscales. Self-assessed spiritual QL in the SELT-M corresponded well with interviewer assessments (test for trend accross ordered groups, P = 0.0023). Conclusions. Overall there is confirming evidence for the hypothesised structure of the SELT-M, especially for the newly developed module on spiritual QL. This module may be used as a module together with other cancer specific QL questionnaire
Isomer-specific effects of CLA on gene expression in human adipose tissue depending on PPARγ2 P12A polymorphism: a double blind, randomized, controlled cross-over study
Optimised generation of heralded Fock states using parametric down conversion
The generation of heralded pure Fock states via spontaneous parametric down
conversion (PDC) relies on perfect photon-number correlations in the output
modes. Correlations in any other degree of freedom, however, degrade the purity
of the heralded state. In this paper, we investigate spectral entanglement
between the two output modes of a periodically poled waveguide. With the intent
of generating heralded 1- and 2-photon Fock states, we expand the output state
of the PDC to second order in photon number. We explore the effects of spectral
filtering and inefficient detection, of the heralding mode, on the count rate,
g(2) and purity of the heralded state, as well as the fidelity between the
resulting state and an ideal Fock state. We find that filtering can decrease
spectral correlations, however, at the expense of the count rate and increased
photon-number mixedness in the heralded output state. As a physical example, we
model a type II PP-KTP waveguide pumped by lasers at wavelengths of 400 nm, 788
nm and 1930 nm. The latter two allow the fulfillment of extended phase matching
conditions in an attempt to eliminate spectral correlations in the PDC output
state without the use of filtering, however, we find that even in these cases,
some filtering is needed to achieve states of very high purity.Comment: 28 pages, 25 figures, revised expressions for two-photon fidelit
Purification and some properties of tartrate-sensitive acid phosphatase from rabbit kidney cortex
MA-XRF imaging on René Magritte’s La condition humaine: insights into the artist’s palette and technique and the discovery of a third quarter of La pose enchantée
- …