Estimation of abdominal fat mass: validity of abdominal bioelectrical impedance analysis and a new model based on anthropometry compared with dual-energy x-ray absorptiometry.

OBJECTIVE: Since abdominal adiposity has been associated with increased risk for chronic diseases, valid and low cost methods to estimate it are needed for clinical and research purposes. The aim of the current study was to develop and validate, using dual-energy x-ray absorptiometry (DXA) as reference method, a model that estimates abdominal fat mass percentage (AFM%) in white postmenopausal women based on simple and easy-to-apply anthropometric measurements. An additional aim was to validate an abdominal bioelectrical impedance analyzer (ViScan) for estimating waist circumference (WC) and AFM% in this group. METHODS: Ninety-one postmenopausal women (mean age, 61.5 y) with body mass index ranging from 20.9 to 42 kg/m2 were randomly divided into one training set (n = 60) and one testing set (n = 31) to develop and validate a model based on anthropometric measurements estimating abdominal fat mass. Furthermore, in all 91 participants, ViScan estimations of WC and AFM% were validated against tape measurement and DXA results. RESULTS: The model developed was AFM% = 4.496 + (0.318 × WC) + 0.342 × suprailiac skinfold (r = 0.834, P < 0.0001). The model had no significant bias (0.25%) and ± 7.5% limits of agreement. ViScan significantly overestimated WC by 7.04 cm and estimated AFM% with no significant bias (-0.13%) and ± 7.6% limits of agreement. CONCLUSIONS: Both the model and ViScan are equally valid against DXA in estimating AFM%. However, ViScan is not valid in estimating WC in white postmenopausal women.

Uncovering the FUTREX-6100XL prediction equation for the percentage body fat.

Based on the near infra-red (NIR) interactance method, the FUTREX company has developed a series of instruments, for the estimation of the body fat percentage (%BF). %BF is estimated through prediction equations incorporated in the instruments, which for the newest models (FUTREX-6100XL and FUTREX-6100A/ZL) are proprietary and they are not published anywhere. This missing knowledge may lead to several misunderstandings and confusion and degrades those instruments to 'black boxes'. The present work uncovers and presents the prediction equation of FUTREX-6100/XL and discusses the contribution of each term of that equation to the %BF. Furthermore, this study presents the method used, which can be used to uncover equations incorporated in other instruments. This method is based on the idea of firstly uncovering the dependence of the equation on each parameter separately and then combining those dependencies to uncover the unknown equation.

Spectroscopic investigations on the depth-dependent degradation gradients of aged triterpenoid varnishes.

The depth-profiles of accelerated aged triterpenoid dammar and mastic varnishes, which had been uncovered by optimized KrF excimer laser ablation (248 nm, 25 ns), were examined by ultraviolet-visible (UV/VIS) spectrophotometry and attenuated total reflection (ATR) Fourier transform infrared (FT-IR) spectroscopy. The results reflect both the optical properties at the bulk (UV/VIS) and the surface (ATR/FT-IR) and establish the presence of degradation gradients across the depth of the degraded natural resin films. It is demonstrated that the UV part of the ambient radiation is absorbed by the deteriorated surface and that the optical densities of the aged varnish decrease as a function of depth. The absorbed UV wavelengths at the surface and the depth-wise reduction of light intensity result in a depth-dependent decrease in carbonyl absorbance and an increase in C-H bending vibration modes of methylene species pointing to structural modification in the triterpenoid mixture across depth.

Analytical study of the chemical and physical changes induced by KrF laser cleaning of tempera paints.

The cleaning of paintings using UV lasers is a growing field of interest in the practice of conservation. In this work, we have studied the chemical and physical changes induced by KrF excimer laser at 248 nm of tempera paint dosimeter systems. The changes have been evaluated by using a range of analytical techniques. These include profilometry; colorimetry; optical and vibrational spectroscopies, such as laser-induced fluorescence (LIF), laser-induced breakdown spectroscopy (LIBS), Fourier transform Raman (FTR), and infrared (FT-IR); and analytical mass spectrometric techniques, such as direct-temperature-resolved mass spectrometry (DTMS) and matrix-assisted laser desorption and ionization mass spectrometry (MALDI-MS). Integration of the results obtained by these techniques allowed the investigation of the nature and degree of change of the irradiated paint systems. Direct laser irradiation induces various degrees of discoloration that depend strongly on the nature of the pigment. This effect takes place mainly on the surface layer of the sample. Degradation of the binding medium occurs in the presence of inorganic pigments, and in some cases, evidence of alterations in the molecular composition of the pigment has been obtained. Varnished systems do not display this discoloration when a thin protective layer is left on the paint. A laser cleaning strategy for varnished paintings should be based on the partial removal of the varnish, leaving a residual layer that shields the underlying pigments from direct laser exposure.