1,019 research outputs found
Spectral and Spin Measurement of Two Small and Fast-Rotating Near-Earth Asteroids
In May 2012 two asteroids made near-miss "grazing" passes at distances of a
few Earth-radii: 2012 KP24 passed at nine Earth-radii and 2012 KT42 at only
three Earth-radii. The latter passed inside the orbital distance of
geosynchronous satellites. From spectral and imaging measurements using NASA's
3-m Infrared Telescope Facility (IRTF), we deduce taxonomic, rotational, and
physical properties. Their spectral characteristics are somewhat atypical among
near-Earth asteroids: C-complex for 2012 KP24 and B-type for 2012 KT42, from
which we interpret the albedos of both asteroids to be between 0.10 and 0.15
and effective diameters of 20+-2 and 6+-1 meters, respectively. Among B-type
asteroids, the spectrum of 2012 KT42 is most similar to 3200 Phaethon and 4015
Wilson-Harrington. Not only are these among the smallest asteroids spectrally
measured, we also find they are among the fastest-spinning: 2012 KP24 completes
a rotation in 2.5008+-0.0006 minutes and 2012 KT42 rotates in 3.634+-0.001
minutes.Comment: 4 pages, 3 figures, accepted for publication in Icaru
Five year mortality and direct costs of care for people with diabetic foot complications are comparable to cancer.
BackgroundIn 2007, we reported a summary of data comparing diabetic foot complications to cancer. The purpose of this brief report was to refresh this with the best available data as they currently exist. Since that time, more reports have emerged both on cancer mortality and mortality associated with diabetic foot ulcer (DFU), Charcot arthropathy, and diabetes-associated lower extremity amputation.MethodsWe collected data reporting 5-year mortality from studies published following 2007 and calculated a pooled mean. We evaluated data from DFU, Charcot arthropathy and lower extremity amputation. We dichotomized high and low amputation as proximal and distal to the ankle, respectively. This was compared with cancer mortality as reported by the American Cancer Society and the National Cancer Institute.ResultsFive year mortality for Charcot, DFU, minor and major amputations were 29.0, 30.5, 46.2 and 56.6%, respectively. This is compared to 9.0% for breast cancer and 80.0% for lung cancer. 5 year pooled mortality for all reported cancer was 31.0%. Direct costs of care for diabetes in general was 80 billion for cancer in 2015. As up to one-third of the direct costs of care for diabetes may be attributed to the lower extremity, these are also readily comparable.ConclusionDiabetic lower extremity complications remain enormously burdensome. Most notably, DFU and LEA appear to be more than just a marker of poor health. They are independent risk factors associated with premature death. While advances continue to improve outcomes of care for people with DFU and amputation, efforts should be directed at primary prevention as well as those for patients in diabetic foot ulcer remission to maximize ulcer-free, hospital-free and activity-rich days
Role of Intrinsic Muscle Atrophy in the Etiology of Claw Toe Deformity in Diabetic Neuropathy May Not Be as Straightforward as Widely Believed
Objective: Clawing of the toes in the diabetic neuropathic foot is believed to be caused by muscle imbalance resulting from intrinsic muscle atrophy. However, experimental data that supports this mechanism is lacking. The aim of this study was to evaluate this hypothesis using magnetic resonance imaging (MRI). Research Design and Methods: In twenty neuropathic diabetic patients, ten with claw toe deformity and ten with normally aligned toes, multiple plane images of the foot and lower leg were acquired using T1-weighted spin-echo MRI. Atrophy of the intrinsic and extrinsic muscles controlling the toes were assessed using a semi-quantitative 5-point atrophy scale. An intrinsic-to-extrinsic foot muscle imbalance score was derived from these atrophy scores and correlation coefficients were established. Results: Mean (SD) intrinsic muscle atrophy score was 3.1 (1.1) for the toe deformity group and 2.6 (1.2) for the non-deformity group (not significantly different). Intrinsic muscle atrophy score was not correlated with degree of toe deformity (r = -0.18). Muscle imbalance score was not significantly different between study groups and not correlated with degree of toe deformity (r = -0.14). Conclusions: Neither intrinsic muscle atrophy nor muscle imbalance discriminated between neuropathic patients with or without claw toe deformity. This suggests that the role of these muscle factors in claw toe development may not be primary or as straightforward as previously believed. These findings shed new light on the etiology of foot deformity in diabetes and suggest a more complex nature of development, potentially involving anatomical and physiological predisposing factor
Pixel classification for automated diabetic foot diagnosis
Worldwide, more than 180 million people suffer from diabetes mellitus. Approximately 50% of these patients will develop complications to their feet. Neuropathy, combined with poor blood supply and biomechanical changes results in a high risk for foot ulcers, which is a key problem in the diabetic foot; when these wounds become infected, this can ultimately result in lower extremity amputation, which has a serious effect on the quality of life of the patient, and causes a large economic burden on society.\ud
\ud
This was the motivation for a collaborate project (Vincent50) in which a photographic foot imaging device was developed. The system allows scanning of the foot soles on a daily basis which may lead to early recognition of foot problems. The goal of the present study is to determine whether pixel classification is a useful intermediate step towards automatically assessing the images of the foot soles for signs of diabetic foot disease. If successful, this approach will further relief health care professionals in assessing the foot and enable the placement of more devices in the future. \ud
\ud
The best agreement between automated recognition and expert diagnosis was achieved with a combination of RGB and derived features, proves that the RGB data is informative with respect to detection of ulcers. However, the automatic detection of pre-signs of ulcers and other anomalies needs more sophistication than pixel classification alone. Firstly, other physical features, such as hyperspectral data, infrared and/or textural features are expected to be more informative. Secondly, we expect to be able to boost the performance by using the context between neighboring pixels. Thirdly, an individualized and normalized classification process might help with the large variability in foot soles between individuals. \u
Inhomogeneities on the surface of 21 Lutetia, the asteroid target of the Rosetta mission
CONTEXT: In July 2010 the ESA spacecraft Rosetta will fly-by the main belt
asteroid 21 Lutetia. Several observations of this asteroid have been so far
performed, but its surface composition and nature are still a matter of debate.
For long time Lutetia was supposed to have a metallic nature due to its high
IRAS albedo. Later on it has been suggested to have a surface composition
similar to primitive carbonaceous chondrite meteorites, while further
observations proposed a possible genetic link with more evolved enstatite
chondrite meteorites. AIMS: In order to give an important contribution in
solving the conundrum of the nature of Lutetia, in November 2008 we performed
visible spectroscopic observations of this asteroid at the Telescopio Nazionale
Galileo (TNG, La Palma, Spain). METHODS: Thirteen visible spectra have been
acquired at different rotational phases. RESULTS: We confirm the presence of a
narrow spectral feature at about 0.47-0.48 micron already found by Lazzarin et
al. (2009) on the spectra of Lutetia. We also find a spectral feature at about
0.6 micron, detected by Lazzarin et al. (2004) on one of their Lutetia's
spectra. More importantly, our spectra exhibit different spectral slopes
between 0.6 and 0.75 micron and, in particular, we found that up to 20% of the
Lutetia surface could have flatter spectra. CONCLUSIONS: We detected a
variation of the spectral slopes at different rotational phases that could be
interpreted as possibly due to differences in the chemical/mineralogical
composition, as well as to inhomogeneities of the structure of the Lutetia's
surface (e.g., the presence of craters or albedo spots) in the southern
hemisphere.Comment: 3 pages, 2 figures. Accepted for publication in Astronomy and
Astrophysics. Updated on 25 March 2010
Space Weathering on Near-Earth Objects investigated by neutral-particle detection
The ion-sputtering (IS) process is active in many planetary environments in
the Solar System where plasma precipitates directly on the surface (for
instance, Mercury, Moon, Europa). In particular, solar-wind sputtering is one
of the most important agents for the surface erosion of a Near-Earth Object
(NEO), acting together with other surface release processes, such as Photon
Stimulated Desorption (PSD), Thermal Desorption (TD) and Micrometeoroid Impact
Vaporization (MIV). The energy distribution of the IS-released neutrals peaks
at a few eVs and extends up to hundreds of eVs. Since all other release
processes produce particles of lower energies, the presence of neutral atoms in
the energy range above 10 eV and below a few keVs (Sputtered High-Energy Atoms
- SHEA) identifies the IS process. SHEA easily escape from the NEO, due to
NEO's extremely weak gravity. Detection and analysis of SHEA will give
important information on surface-loss processes as well as on surface elemental
composition. The investigation of the active release processes, as a function
of the external conditions and the NEO surface properties, is crucial for
obtaining a clear view of the body's present loss rate as well as for getting
clues on its evolution, which depends significantly on space weather. In this
work, an attempt to analyze the processes that take place on the surface of
these small airless bodies, as a result of their exposure to the space
environment, has been realized. For this reason a new space weathering model
(Space Weathering on NEO - SPAWN), is presented. Moreover, an instrument
concept of a neutral-particle analyzer specifically designed for the
measurement of neutral density and the detection of SHEA from a NEO is proposedComment: 36 page
Synthesis, properties, antitumor and antibacterial activity of new Pt(II) and Pd(II) complexes with 2,2'-dithiobis(benzothiazole) ligand
Mono- and binuclear Pt(II) and Pd(II) complexes with 2,20-dithiobis(benzothiazole) (DTBTA) ligand are
reported. [Pt(DTBTA)(DMSO)Cl]Cl 19CHCl3 (1) and [Pd2(m-Cl)2(DTBTA)2]Cl2 (2) have been synthesized and
structurally characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy, MS spectrometry
and the content of platinum and palladium was determined using a flame atomic spectrometer. Two different
coordination modes of 1 and 2 complexes were found; in both complexes, the coordination of Pt(II)
and Pd(II) ions involves the N(3) atoms of the ligand but the binuclear complex 2, is a cis-chloro-bridged
palladium complex. Evaluation of their in vitro antitumor activity against two human tumor cell lines
human breast cancer (MCF-7) and hepatocellular carcinoma (HepG2); and their antimicrobial activity
against Escherichia coli and Kokuria rhizophila was performed. Only complex 1 showed a dose- and
time-dependent cytotoxic activity against the two tumor cell lines, associated to apoptosis and accumulation
of treated cells in G0/G1 phase of cell cycle, while both 1 and 2 exhibited antimicrobial activity
with complex 1 much more potent. The study on intracellular uptake in both MCF-7 and HepG2 cell lines
revealed that only platinum of complex 1 is present inside the cells, suggesting a different mode of action
of the two compounds. This was also in agreement with the results obtained for the antitumor and
antibacterial activity
Molecular characterization of intergeneric hybrids between Malus and Pyrus
Apple (Malus) and pear (Pyrus) are economically important fruit crops well known for their unique textures, flavours, and nutritional qualities. Both genera are characterised by a distinct pattern of secondary metabolites, which directly affect not only resistance to certain diseases, but also have significant impacts on the flavour and nutritional value of the fruit. The identical chromosome numbers, similar genome size, and their recent divergence date, together with DNA markers have shown that apple and pear genomes are highly co-linear. This study utilized comparative genomic approaches, including simple sequence repeats, high resolution single nucleotide polymorphism melting analysis, and single nucleotide polymorphism chip analysis to identify genetic differences among hybrids of Malus and Pyrus, and F2 offspring. This research has demonstrated and validated that these three marker types, along with metabolomics analysis are very powerful tools to detect and confirm hybridity of progeny derived from crosses between apple and pear in both cross directions. Furthermore, this work analysed the genus-specific metabolite patterns and the resistance to fire blight (Erwinia amylovora) in progeny. The findings of this work will enhance and accelerate the breeding of novel tree fruit crops that benefit producers and consumers, by enabling marker assisted selection of desired traits introgressed between pear and apple
- …