20,573 research outputs found
Searching for Ground Truth: a stepping stone in automating genre classification
This paper examines genre classification of documents and
its role in enabling the effective automated management of digital documents by digital libraries and other repositories. We have previously presented genre classification as a valuable step toward achieving automated extraction of descriptive metadata for digital material. Here, we present results from experiments using human labellers, conducted to assist in genre characterisation and the prediction of obstacles which need to be overcome by an automated system, and to contribute to the process of creating a solid testbed corpus for extending automated genre classification and testing metadata extraction tools across genres. We also describe the performance of two classifiers based on image and stylistic modeling features in labelling the data resulting from the agreement of three human labellers across fifteen genre classes.
Body composition, IGF1 status, and physical functionality in nonagenarians: implications for osteosarcopenia
OBJECTIVES:
Body composition alterations occur during aging. The purpose of the present analysis was to explore the functional consequences of the overlap of sarcopenia and osteoporosis, and the potential role of insulin-like growth factor 1 (IGF1) in their development in the oldest old.
SETTING AND PARTICIPANTS:
Eighty-seven nonagenarians from the Louisiana Healthy Aging Study were included.
MEASURES:
The definition of sarcopenia was based on appendicular lean mass (ALM). Osteoporosis was diagnosed based on bone mineral density (BMD) T score. Four phenotypes were compared: (1) healthy body composition, that is, nonosteoporotic nonsarcopenic (CO, control group), (2) osteoporotic (O, low BMD T score), (3) sarcopenic (S, low ALM), and (4) osteosarcopenic (OS, low BMD T score and low ALM). Sex- and age-specific IGF1-Standard Deviation Scores (SDS) were calculated. The Continuous Scale-Physical Functional Performance (CS-PFP) test was performed.
RESULTS:
In OS men, IGF1-SDS values (-0.61 ±0.37 vs -0.04 ± 0.52, P = .02) were lower than those in CO males (control group), whereas IGF1-SDS were similar in the 4 body composition phenotypes in women. In men only, ALM was positively associated with IGF1-SDS values (P = .01) independent of age and C-reactive protein concentration. Regarding bone health, we found no association between IGF1-SDS values and BMD. IGF1-SDS was not associated with functional performance (CS-PFP) in men and women.
CONCLUSIONS/IMPLICATIONS:
IGF1 sensitivity in skeletal muscle and bone may differ by sex in the oldest old. IGF1 status did not appear to affect physical functionality. Determinants and clinical and functional characteristics of osteosarcopenia need to be further investigated in order to define conclusive diagnostic criteria
Anticancer effects of gossypetin from Hibiscus sabdariffa in oral squamous cell carcinoma
Objective: Gossypetin, isolated from Hibiscus sabdariffa L, has been shown to have various pharmacological effects including anti-inflammatory and antibacterial activity against various diseases. However, since the effect of gossypetin in oral cancer remains to be reported, we aimed to investigate the anticancer activity and mechanisms of gossypetin in oral squamous cell carcinoma (OSCC). Methodology: The proliferation of OSCC cells was evaluated by cell viability and soft agar colony assays. The effects of gossypetin on the migration and invasion of OSCC cells was investigated by wound healing and transwell invasion assays, respectively. Apoptosis and cell cycle arrest were measured by flow cytometry. Moreover, the anticancer mechanism of gossypetin in OSCC cells was analyzed by western blotting. Results: Gossypetin inhibited the proliferation, migration, and invasion of OSCC cells and induced apoptosis by upregulating the Bax/Bcl-2 ratio and cell cycle arrest at the G2/M phase. Furthermore, gossypetin regulated the activation of extracellular signal-regulated kinase and nuclear factor-kappa B. Conclusion: Results showed that gossypetin inhibits the proliferation, migration, and invasion of OSCC cells and triggers apoptosis and cell cycle arrest in OSCC. Therefore, gossypetin has the potential for use as a chemopreventive agent in oral cancer
A Single-Molecule Study on the Structural Damage of Ultraviolet Radiated DNA
The structural damage of double-stranded DNA under UV radiation was examined using single-molecule fluorescence microscopy. Compared to undamaged DNA, the diffusion coefficient of λ-DNA was significantly increased with 12 min or 20 min of radiation but remained unchanged for 40 min of exposure possibly due to strand crosslinking. The structural damage of DNA was further examined using transmission electron microscopy which revealed kinks and sharp bends along the DNA backbone
The effect of winter frozen season changes on Northern Hemisphere vegetation canopy growth determined from satellite microwave and optical remote sensing
Characterizing DNA Condensation and Conformational Changes in Organic Solvents
Organic solvents offer a new approach to formulate DNA into novel structures suitable for gene delivery. In this study, we examined the in situ behavior of DNA in N, N-dimethylformamide (DMF) at low concentration via laser light scattering (LLS), TEM, UV absorbance and Zeta potential analysis. Results revealed that, in DMF, a 21bp oligonucleotide remained intact, while calf thymus DNA and supercoiled plasmid DNA were condensed and denatured. During condensation and denaturation, the size was decreased by a factor of 8–10, with calf thymus DNA forming spherical globules while plasmid DNA exhibited a toroid-like conformation. In the condensed state, DNA molecules were still able to release the counterions to be negatively charged, indicating that the condensation was mainly driven by the excluded volume interactions. The condensation induced by DMF was reversible for plasmid DNA but not for calf thymus DNA. When plasmid DNA was removed from DMF and resuspended in an aqueous solution, the DNA was quickly regained a double stranded configuration. These findings provide further insight into the behavior and condensation mechanism of DNA in an organic solvent and may aid in developing more efficient non-viral gene delivery systems
Role of the Brans-Dicke scalar in the holographic description of dark energy
We study cosmological application of the holographic energy density in the
Brans-Dicke theory. Considering the holographic energy density as a dynamical
cosmological constant, it is more natural to study it in the Brans-Dicke theory
than in general relativity. Solving the Friedmann and Brans-Dicke field
equations numerically, we clarify the role of Brans-Dicke field during
evolution of the universe. When the Hubble horizon is taken as the IR cutoff,
the equation of state (w_{\Lmd}) for the holographic energy density is
determined to be 5/3 when the Brans-Dicke parameter \omg goes infinity. This
means that the Brans-Dicke field plays a crucial role in determining the
equation of state. For the particle horizon IR cutoff, the Brans-Dicke scalar
mediates a transition from w_{\Lmd} = -1/3 (past) to w_{\Lmd} = 1/3
(future). If a dust matter is present, it determines future equation of state.
In the case of future event horizon cutoff, the role of the Brans-Dicke scalar
and dust matter are turned out to be trivial, whereas the holographic energy
density plays an important role as a dark energy candidate with w_{\Lmd} =-1.Comment: 10pages, 3figures, version to appear in PL
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