95 research outputs found
Hepatocellular carcinoma detected by regular surveillance: Does timely confirmation of diagnosis matter?
AbstractBackgroundAlthough current guidelines recommended surveillance of hepatocellular carcinoma, prognosis in patients undergoing enhanced follow-up has yet to be evaluated.AimsExamine outcomes of hepatocellular carcinoma diagnosed during enhanced follow-up.MethodsDuring 2010–2012, 194 patients underwent ultrasonography surveillance were diagnosed with hepatocellular carcinoma and divided into: (A) immediate diagnosis (N=105, 54.1%) after positive ultrasonography, (B) enhanced follow-up: (N=38, 19.6%) for initial negative recall procedures, (C) late call back: (N=28, 14.4%) recall procedures were deferred after positive ultrasonography, and (D) beyond ultrasonography: (N=23, 11.9%) surveillance ultrasonography had been negative.ResultsMedian time from positive ultrasonography to confirmation of hepatocellular carcinoma were 9.5 months (2–67) in the Group B and 6.5 months (3–44) in the Group C. Stage distribution and 3-year survival rates were similar amongst all Groups. Surveillance intervals longer than 6 months were associated with the non-curative stage (3.7% vs. 12.5%, p=0.04). Nine (4.6%) patients underwent surveillance were diagnosed as Barcelona-Clinic Liver Cancer stage C.ConclusionEnhanced follow-up by current guidelines is appropriate that treatment can be deferred until a definite diagnosis. Despite optimal surveillance interval and recall policies, few non-curative stage diagnoses seemed inevitable under current standard of care
Dihydrolipoic Acid Induces Cytotoxicity in Mouse Blastocysts through Apoptosis Processes
α-Lipoic acid (LA) is a thiol with antioxidant properties that protects against oxidative stress-induced apoptosis. LA is absorbed from the diet, taken up by cells and tissues, and subsequently reduced to dihydrolipoic acid (DHLA). In view of the recent application of DHLA as a hydrophilic nanomaterial preparation, determination of its biosafety profile is essential. In the current study, we examined the cytotoxic effects of DHLA on mouse embryos at the blastocyst stage, subsequent embryonic attachment and outgrowth in vitro, in vivo implantation by embryo transfer, and early embryonic development in an animal model. Blastocysts treated with 50 μM DHLA exhibited significantly increased apoptosis and a corresponding decrease in total cell number. Notably, the implantation success rates of blastocysts pretreated with DHLA were lower than that of their control counterparts. Moreover, in vitro treatment with 50 μM DHLA was associated with increased resorption of post-implantation embryos and decreased fetal weight. Data obtained using an in vivo mouse model further disclosed that consumption of drinking water containing 100 μM DHLA led to decreased early embryo development, specifically, inhibition of development to the blastocyst stage. However, it appears that concentrations of DHLA lower than 50 μM do not exert a hazardous effect on embryonic development. Our results collectively indicate that in vitro and in vivo exposure to concentrations of DHLA higher than 50 μM DHLA induces apoptosis and retards early pre- and post-implantation development, and support the potential of DHLA to induce embryonic cytotoxicity
Atomistic nucleation sites of Pt nanoparticles on N-doped carbon nanotubes
[[abstract]]The atomistic nucleation sites of Pt nanoparticles (Pt NPs) on N-doped carbon nanotubes (N-CNTs) were investigated using C and N K-edge and Pt L3-edge X-ray absorption near-edge structure (XANES)/extended X-ray absorption fine structure (EXAFS) spectroscopy. Transmission electron microscopy and XANES/EXAFS results revealed that the self-organized Pt NPs on N-CNTs are uniformly distributed because of the relatively high binding energies of the adsorbed Pt atoms at the imperfect sites. During the atomistic nucleation process of Pt NPs on N-CNTs, stable Pt–C and Pt–N bonds are presumably formed, and charge transfer occurs at the surface/interface of the N-CNTs. The findings in this study were consistent with density functional theory calculations performed using cluster models for the undoped, substitutional-N-doped and pyridine-like-N-doped CNTs.[[journaltype]]國外[[incitationindex]]SCI[[booktype]]紙本[[countrycodes]]GB
Localized Gaussian Type Orbital−Periodic Boundary Condition−Density Functional Theory Study of Infinite-Length Single-Walled Carbon Nanotubes with Various Tubular Diameters
[[abstract]]The detailed geometrical structures of zigzag and armchair type single-walled carbon nanotubes (SWCNTs) with infinite tubular length were investigated using localized Gaussian type orbital−periodic boundary condition−density functional theory (LGTO−PBC−DFT) method. The structures of (n, 0) zigzag SWCNTs were optimized for n = 5−21, (n, n) armchair SWCNTs for n = 3−12. For comparison, the optimized geometry of a two-dimensional graphite sheet was also calculated. It was found that the optimized structures of the SWCNTs showed two C−C bond lengths that decrease with an increase in the tubular diameter. More specifically, the two bond lengths converged with those found in the two-dimensional graphite sheet. We also found a degeneracy in the highest occupied crystal orbitals if identical bond lengths were employed for the zigzag SWCNTs and the two-dimensional graphite sheet. This implies that the two different bond lengths found in the zigzag SWCNTs and the two-dimensional graphite sheet are probably due to the Jahn−Teller effect. The armchair SWCNTs show two slightly different bond lengths if the diameter is less than 12 Å; otherwise they are almost identical, approaching the longer bond length of the two-dimensional graphite sheet. This can be due to the fact that the armchair SWCNTs do not have degeneracy in occupied crystal orbitals for identical C−C bond lengths. The crossing point of the conducting and valence bands of each armchair SWCNT were also calculated and show a diameter dependence in which the deviation from 2π/3a decreases as diameter increases.[[journaltype]]國外[[incitationindex]]SCI[[booktype]]紙本[[countrycodes]]US
Planarized Trench Isolation of In<sub>0.52</sub>Al<sub>0.48</sub>As/In<sub>0.8</sub>Ga<sub>0.2</sub>As Metamorphic High-Electron-Mobility Transistor by Liquid Phase Chemical Enhanced Oxidation
The liquid phase chemical enhanced oxidation (LPCEO) technique was applied to achieve planarized isolation of a high-indium-content In0.52Al0.48As/In0.8Ga0.2As metamorphic high-electron-mobility transistor (MHEMT). Through a simple, low-temperature process not requiring costly machinery, electrical isolation of components was accomplished. In addition, multiple advantages were gained, including the production of planarized surfaces, low pollution, and reduction in the subsequent disposal of wet etching solution and costs for dry etching or ion implantation. Because of the decrease in lateral defect density caused by wet or dry etching and the further decrease in gate leakage current owing to the isolated oxide film, the performance of devices, with improved DC characteristics, less flicker noise, and enhanced high-frequency performance, can be increased
Intramolecular Vibrations in Low-Frequency Normal Modes of Amino Acids: l‑Alanine in the Neat Solid State
This
paper presents a theoretical analysis of the low-frequency
phonons of l-alanine by using the solid-state density functional
theory at the Γ point. We are particularly interested in the
intramolecular vibrations accessing low-frequency phonons via harmonic
coupling with intermolecular vibrations. A new mode-analysis method
is introduced to quantify the vibrational characteristics of such
intramolecular vibrations. We find that the torsional motions of COO<sup>–</sup> are involved in low-frequency phonons, although COO<sup>–</sup> is conventionally assumed to undergo localized torsion.
We also find the broad distributions of intramolecular vibrations
relevant to important functional groups of amino acids, e.g., the
COO<sup>–</sup> and NH<sub>3</sub><sup>+</sup> torsions, in
the low-frequency phonons. The latter finding is illustrated by the
concept of frequency distribution of vibrations. These findings may
lead to immediate implications in other amino acid systems
Characteristics of Low-Frequency Molecular Phonon Modes Studied by THz Spectroscopy and Solid-State ab Initio Theory: Polymorphs I and III of Diflunisal
THz absorption spectra of two polymorphs
of diflunisal, form I
and form III, exhibit distinct features due to the influence of packing
conformations on the frequency distributions and IR activities of
gamma point phonon modes within the 100 cm<sup>–1</sup> region.
In order to understand the origins of these THz modes, we perform
a detailed mode analysis. The result shows that although the spectral
features are different, these low-frequency phonon modes of the two
molecular polymorphs have similar vibrational characteristics in terms
of harmonic couplings of intermolecular and intramolecular vibrations
- …