4,177 research outputs found
Metabolic responses of osteochondral allografts to re-warming after MOPS(TM) preservation versus standard of care storage
Osteoarthritis (OA) affects ~90% of people older than 65, and associated costs top $100 billion annually in the U.S. One treatment available for large cartilage defects seen in osteoarthritis is osteochondral allograft (OCA) transplantation. Currently, tissue banks store OCAs at 4 degree C and implantation is recommended within 28 days after procurement due to significant loss in chondrocyte viability after this time. Because mandatory disease screening protocols typically take 14 days to complete, the window for surgical implantation is narrow, which severely limits clinical use. The MOPS(TM) protocol can maintain OCAs for 56 days. In this study, OCAs stored using MOPS(TM) and SOC protocol were assessed for cell viability and metabolic biomarker production
Solar Neutron Events of October-November 2003
During the period when the Sun was intensely active on October-November 2003,
two remarkable solar neutron events were observed by the ground-based neutron
monitors. On October 28, 2003, in association with an X17.2 large flare, solar
neutrons were detected with high statistical significance (6.4 sigma) by the
neutron monitor at Tsumeb, Namibia. On November 4, 2003, in association with an
X28 class flare, relativistic solar neutrons were observed by the neutron
monitors at Haleakala in Hawaii and Mexico City, and by the solar neutron
telescope at Mauna Kea in Hawaii simultaneously. Clear excesses were observed
at the same time by these detectors, with the significance calculated as 7.5
sigma for Haleakala, and 5.2 sigma for Mexico City. The detector onboard the
INTEGRAL satellite observed a high flux of hard X-rays and gamma-rays at the
same time in these events. By using the time profiles of the gamma-ray lines,
we can explain the time profile of the neutron monitor. It appears that
neutrons were produced at the same time as the gamma-ray emission.Comment: 35 pages, 21 figures, accepted for publication in Ap
Profiling of VEGFs and VEGFRs as Prognostic Factors in Soft Tissue Sarcoma: VEGFR-3 Is an Independent Predictor of Poor Prognosis
BACKGROUND: In non-gastrointestinal stromal tumor soft tissue sarcoma (non-GIST STS) optimal treatment is surgery with wide resection margins. Vascular endothelial growth factors (VEGFs) and receptors (VEGFRs) are known to be key players in the initiation of angiogenesis and lymphangiogenesis. This study investigates the prognostic impact of VEGFs and VEGFRs in non-GIST STS with wide and non-wide resection margins. METHODS: Tumor samples from 249 patients with non-GIST STS were obtained and tissue microarrays were constructed for each specimen. Immunohistochemistry was used to evaluate the expressions of VEGF-A, -C and -D and VEGFR-1, -2 and -3. RESULTS: In the univariate analyses, VEGF-A (P=0.040) in the total material, and VEGF-A (P=0.018), VEGF-C (P=0.025) and VEGFR-3 (P=0.027) in the subgroup with wide resection margins, were significant negative prognostic indicators of disease-specific survival (DSS). In the multivariate analysis, high expression of VEGFR-3 (P=0.042, HR=1.907, 95% CI 1.024-3.549) was an independent significant negative prognostic marker for DSS among patients with wide resection margins. CONCLUSION: VEGFR-3 is a strong and independent negative prognostic marker for non-GIST STSs with wide resection margins
Particle trajectories in linearized irrotational shallow water flows
We investigate the particle trajectories in an irrotational shallow water
flow over a flat bed as periodic waves propagate on the water's free surface.
Within the linear water wave theory, we show that there are no closed orbits
for the water particles beneath the irrotational shallow water waves. Depending
on the strength of underlying uniform current, we obtain that some particle
trajectories are undulating path to the right or to the left, some are looping
curves with a drift to the right and others are parabolic curves or curves
which have only one loop
Competition between normal and intruder states inside the "Island of Inversion"
The beta decay of the exotic 30Ne (N=20) is reported. For the first time, the
low-energy level structure of the N=19, 30Na (Tz = 4), is obtained from
beta-delayed gamma spectroscopy using fragment-beta-gamma-gamma coincidences.
The level structure clearly displays "inversion", i.e., intruder states with
mainly 2p2h configurations displacing the normal states to higher excitation
energies. The good agreement in excitation energies and the weak and
electromagnetic decay patterns with Monte Carlo Shell Model calculations with
the SDPF-M interaction in the sdpf valence space illustrates the small d3/2 -
f7/2 shell gap. The relative position of the "normal dominant" and "intruder
dominant" excited states provides valuable information to understand better the
N=20 shell gap.Comment: 4 pages, 5 figure
Nanostratification of optical excitation in self-interacting 1D arrays
The major assumption of the Lorentz-Lorenz theory about uniformity of local
fields and atomic polarization in dense material does not hold in finite groups
of atoms, as we reported earlier [A. E. Kaplan and S. N. Volkov, Phys. Rev.
Lett., v. 101, 133902 (2008)]. The uniformity is broken at sub-wavelength
scale, where the system may exhibit strong stratification of local field and
dipole polarization, with the strata period being much shorter than the
incident wavelength. In this paper, we further develop and advance that theory
for the most fundamental case of one-dimensional arrays, and study nanoscale
excitation of so called "locsitons" and their standing waves (strata) that
result in size-related resonances and related large field enhancement in finite
arrays of atoms. The locsitons may have a whole spectrum of spatial
frequencies, ranging from long waves, to an extent reminiscent of ferromagnetic
domains, -- to super-short waves, with neighboring atoms alternating their
polarizations, which are reminiscent of antiferromagnetic spin patterns. Of
great interest is the new kind of "hybrid" modes of excitation, greatly
departing from any magnetic analogies. We also study differences between
Ising-like near-neighbor approximation and the case where each atom interacts
with all other atoms in the array. We find an infinite number of "exponential
eigenmodes" in the lossless system in the latter case. At certain "magic"
numbers of atoms in the array, the system may exhibit self-induced (but linear
in the field) cancellation of resonant local-field suppression. We also studied
nonlinear modes of locsitons and found optical bistability and hysteresis in an
infinite array for the simplest modes.Comment: 39 pages, 5 figures; v2: Added the Conclusions section, corrected a
typo in Eq. (5.3), corrected minor stylistic and grammatical imperfection
Reversal of the Charge Transfer between Host and Dopant Atoms in Semiconductor Nanocrystals
We present ab initio density functional calculations that show P (Al) dopant
atoms in small hydrogen-terminated Si crystals to be negatively (positively)
charged. These signs of the dopant charges are reversed relative to the same
dopants in bulk Si. We predict this novel reversal of the dopant charge (and
electronic character of the doping) to occur at crystal sizes of order 100 Si
atoms. We explain it as a result of competition between fundamental principles
governing charge transfer in bulk semiconductors and molecules and predict it
to occur in nanocrystals of most semiconductors.Comment: 4 pages, 4 figures (3 in color), 2 table
Observations of the geology and geomorphology of the 1999 Marsokhod test site
The Marsokhod rover returned data from six stations that were used to decipher the geomorphology and geology of a region not previously visited by members of the geomorphology field team. Satellite images and simulated descent images provided information about the regional setting. The landing zone was on an alluvial apron flanking a mountain block to the west and playa surface to the east. Rover color images, infrared spectra analysis of the mountains, and the apron surface provided insight into the rock composition of the nearby mountains. From the return data the geomorphology team interpreted the region to consist of compressionally deformed, ancient marine sediments and igneous rocks exposed by more recent extensional tectonics. Unconsolidated alluvial materials blanket the lower flanks of the mountains. An ancient shoreline cut into alluvial material marks a high stand of water during a past, wetter climate period. Playa sediments floor a present-day, seasonally, dry lake. Observations made by the rover using panoramic and close-up (hand specimensâscale) image data and color scene data confirmed the presence of boulders, cobbles, and fines of various provinces. Rover traverses to sites identified as geologically distinct, such as a fan, channel, shoreline, and playa, provided useful clues to the geologic interpretations. Analysis of local rocks was given context only through comparison with distant geologic features. These results demonstrated the importance of a multifaceted approach to site interpretation through comparison of interpretations derived by differing geologic techniques
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