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Microscopic Characteristics (microscopic + characteristic)

Distribution by Scientific Domains

Chemistry	28%

Selected Abstracts

Fatty acid synthase expression in squamous cell carcinoma of the tongue: clinicopathological findings

ORAL DISEASES, Issue 4 2008
SD Silva
Background:, Overexpression of fatty acid synthase (FAS), the cytosolic enzyme responsible for the conversion of dietary carbohydrates to fatty acids, has been reported in several human malignancies and pointed as a potential prognostic marker for some tumors. This study investigated whether FAS immunohistochemical expression is correlated with the clinicopathological characteristics of oral squamous cell carcinoma (OSCC). Materials and methods:, The clinical features of 102 patients with OSCC of the tongue treated in a single institution were obtained from the medical records and all histopathological diagnoses were reviewed. The expression of FAS was determined by the standard immunoperoxidase technique in formalin-fixed and paraffin-embedded specimens and correlated with the clinicopathological characteristics of the tumors. Results:, Eighty-one cases (79.41%) were positive for FAS. Microscopic characteristics such as histological grade (P < 0.05), lymphatic permeation (P < 0.001), perineural infiltration (P < 0.05), and nodal metastasis (P < 0.02) were associated with FAS status. A significantly lower survival probability for patients with advanced clinical stage (log-rank test, P < 0.001), lymph nodes metastasis (log-rank test, P < 0.001), presence of vascular permeation (log-rank test, P = 0.05), and perineural invasion (log-rank test, P = 0.01) was observed in the studied samples. Conclusion:, The expression of FAS in OSCC of the tongue is associated with the microscopic characteristics that determine disease progression and prognosis. [source]

Molecular dynamics and multiscale homogenization analysis of seepage/diffusion problem in bentonite clay

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 12 2002
Y. Ichikawa
Abstract A scheme combining a molecular behaviour and macro-continuum phenomenon is presented for bentonite clay, which is a key component of a barrier system for disposal and containment of hazardous wastes. On designing a disposal facility we use a macro-phenomenological model. However the existing model is not sufficiently effective. Bentonite is a microinhomogeneous material. Properties of the saturated bentonite are characterized by montmorillonite and water, called montmorillonite hydrate. Since the crystalline structure of montmorillonite determines the fundamental properties of the montmorillonite hydrate, we analyse its molecular behaviour by applying a molecular dynamics simulation to enquire into the physicochemical properties of the montmorillonite hydrate such as diffusivity of chemical species. For extending the microscopic characteristics of constituent materials to a macroscopic diffusion behaviour of the microinhomogeneous material we apply a multiscale homogenization analysis, especially in order to treat micro-level of adsorption behaviour. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Nucleophilic and acid catalyst behavior of a protic ionic liquid in a molecular reaction media.

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 5 2009
Part
Abstract This work presents a new approach using ionic liquids, namely ethylammonium nitrate. The aim was to analyze how the addition of small amounts of a protic ionic liquid to a pure molecular solvent, modifies the microscopic characteristics of a reaction medium. In order to achieve this, a kinetic study of nucleophilic aromatic substitution reactions between 1-fluoro-2,4-dinitrobenzene and 1-butylamine or piperidine was developed in this type of binary mixtures. We have detected nucleophiles competition originated by the presence of the ionic solvent at very low concentrations, observing the ethylamine derivative as the main substitution product. Moreover, in the light of previous results we have confirmed that the protic ionic liquid can act as both Brönsted acid and/or nucleophile. In this connection, we have selected the nucleophilic addition of amines to carbonyl compounds as reaction model. The protic ionic liquid in the presence of aromatic aldehydes substituted by electron-donating groups makes possible the formation of the corresponding imines with good yields. The results demonstrated that the influence of the protic ionic liquid is very important in the course of both reaction systems. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Isolation of clinically relevant fungal species from solid waste and environment of dental health services

LETTERS IN APPLIED MICROBIOLOGY, Issue 4 2010
C.D. Vieira
Abstract Aims:, This study was undertaken to detect, identify and determine antifungal susceptibility of yeast strains isolated from dental solid waste and to evaluate airborne fungi in the Brazilian dental health care environment and in the waste storage room. Methods and Results:, A group of 17 yeast strains were identified by macroscopic and microscopic characteristics, API 20C Aux system and Multiplex PCR. All 104 airborne fungal colonies were identified by macroscopic and microscopic morphology. The CLSI broth microdilution method was utilized as the susceptibility test. Candida parapsilosis was the prevailing yeast species recovered from waste, followed by Rhodotorula glutinis. Three strains of Candida guilliermondii presented minimal inhibitory concentration values considered to be susceptible dose dependent (2 ,g ml,1) to voriconazole. Of all airborne fungal species, 69% were recovered from the waste storage room and 31% were recovered from the clinical/surgical environment. Most of them were identified as Cladosporium spp. Conclusions:, These findings reinforce the potential risk of waste handling and point out the need for safe management to minimize the spread of these agents to the environment. Filamentous fungi isolation in almost all sampled environments indicates that a periodic monitoring of airborne microbiota in the dental health care service environment is required. Significance and Impact of the Study:, The survival of yeast strains for 48 h suggests that dental waste should be carefully controlled and monitored. [source]

Fatty acid synthase expression in squamous cell carcinoma of the tongue: clinicopathological findings

Estimation of Centres and Radial Intensity Profiles of Spherical Nano-Particles in Digital Microscopy

BIOMETRICAL JOURNAL, Issue 2 2007
Mats Kvarnström
Abstract Control of the microscopic characteristics of colloidal systems is critical in a wealth of application areas, ranging from food to pharmaceuticals. To assist in estimating these characteristics, we present a method for estimating the positions of spherical nano-particles in digital microscopy images. The radial intensity profiles of particles, which depend on the distances of the particles from the focal plane of the light microscope and have no closed functional form, are modelled using a local quadratic kernel estimate. We also allow for the case where pixel values are censored at an upper limit of 255. Standard errors of centre estimates are obtained using a sandwich estimator which takes into account spatial autocorrelation in the errors. The approach is validated by a simulation study. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Polymer Matrix Effects on the Nonlinear Optical Response of Incorporated Chromophore: New Analytical Models

CHEMPHYSCHEM, Issue 10 2006
Marina Yu.
Abstract A new approach aimed at the modeling of the nonlinear optical (NLO) response of a dipole chromophore incorporated into a locally anisotropic, deformable, polarizable polymer matrix is suggested. The general continuum methodology is used with a specific cavity ansatz being employed; the cavity is chosen to be conformal to the characteristic ellipsoid of the generalized permittivity tensor of the polymer medium. The suggested ansatz allows the electrostatic boundary value problem to be solved analytically, and the local field experienced by the chromophore in the polymer electret to be found. Four analytically solvable models, which correspond to two singular and two nonsingular models, are considered; in two of them the chromophore is characterized by singular dipole and quadrupole moments; the other two use the approximation of the electric moment of the chromophore with that of the polarized ellipsoid. The relation between the macroscopic polymer properties and the microscopic characteristics of the NLO chromophore is established. The compliance of the obtained formulas for the local field with those of the classical Onsager approach is analyzed, and their specific features are considered. [source]