Raman analysis of multilayer automotive paints in forensic science: measurement variability and depth profile?

The aim of this work is to study the influence of several analytical parameters on the variability of Raman spectra of paint samples. In the present study, microtome thin section and direct (no preparation) analysis are considered as sample preparation. In order to evaluate their influence on the measures, an experimental design such as 'fractional full factorial' with seven factors (including the sampling process) is applied, for a total of 32 experiments representing 160 measures. Once the influence of sample preparation highlighted, a depth profile of a paint sample is carried out by changing the focusing plane in order to measure the colored layer under a clearcoat. This is undertaken in order to avoid sample preparation such a microtome sectioning. Finally, chemometric treatments such as principal component analysis are applied to the resulting spectra. The findings of this study indicate the importance of sample preparation, or more specifically, the surface roughness, on the variability of the measurements on a same sample. Moreover, the depth profile experiment highlights the influence of the refractive index of the upper layer (clearcoat) when measuring through a transparent layer.

Effects of computing parameters and measurement locations on the estimation of 3D NPS in non-stationary MDCT images.

The goal of this study was to investigate the impact of computing parameters and the location of volumes of interest (VOI) on the calculation of 3D noise power spectrum (NPS) in order to determine an optimal set of computing parameters and propose a robust method for evaluating the noise properties of imaging systems. Noise stationarity in noise volumes acquired with a water phantom on a 128-MDCT and a 320-MDCT scanner were analyzed in the spatial domain in order to define locally stationary VOIs. The influence of the computing parameters in the 3D NPS measurement: the sampling distances bx,y,z and the VOI lengths Lx,y,z, the number of VOIs NVOI and the structured noise were investigated to minimize measurement errors. The effect of the VOI locations on the NPS was also investigated. Results showed that the noise (standard deviation) varies more in the r-direction (phantom radius) than z-direction plane. A 25 × 25 × 40 mm(3) VOI associated with DFOV = 200 mm (Lx,y,z = 64, bx,y = 0.391 mm with 512 × 512 matrix) and a first-order detrending method to reduce structured noise led to an accurate NPS estimation. NPS estimated from off centered small VOIs had a directional dependency contrary to NPS obtained from large VOIs located in the center of the volume or from small VOIs located on a concentric circle. This showed that the VOI size and location play a major role in the determination of NPS when images are not stationary. This study emphasizes the need for consistent measurement methods to assess and compare image quality in CT.

Off-axis low-coherence interferometry for surface topology measurement.

In this communication we introduce a low or reduced coherence interferometry technique that can be used to retrieve surface topology on samples with high roughness. Moreover, we will show that the approach enables surface topology measurement also at the interface of so-called turbid media, where multiple scattering inside tissues can be a major issue, preventing accurate measurements.

Measurement of plasma endothelin-1 in experimental hypertension and in healthy subjects.

BACKGROUND: Endothelin-1 is an endothelium-derived potent vasoconstrictor peptide of 21 amino acids. To establish reference values in different models of hypertension and in human subjects an assay for plasma immunoreactive endothelin-1 (ET-1) was optimized. METHODS: ET-1 is extracted by acetone from 1 mL of plasma and subjected to a sensitive enzyme-linked immunosorbent assay. RESULTS: The detection limit for plasma ET-1 is 0.05 fmol/mL. Mean recoveries of the 1, 2, 5, and 10 fmol of ET-1 added to 1 mL of plasma were 66%, 75%, 85%, and 92%, respectively. Within- and between-assay coefficients of variation were < or =12% and < or =10%, respectively. Assay accuracy was demonstrated by consistent recoveries of added ET-1 over the entire physiologic range of plasma concentrations and by the linearity of ET-1 concentrations measured in serially diluted plasma extracts (r = 0.99). No ET-1 was detected when albumin buffer was extracted instead of plasma. Using this method, we found increased ET-1 levels in plasma of three experimental rat models of hypertension: stroke prone spontaneously hypertensive rats (SP-SHR), deoxycorticosterone acetate-salt hypertensive rats, and one kidney-one clip hypertensive rats. In contrast, plasma ET-1 levels of SHR were half those of normotensive Wistar rats. In two kidney-one clip hypertensive rats, plasma ET-1 concentrations were not different from those found in sham-operated control rats. Plasma ET-1 concentrations of 37 healthy men were 0.85 +/- 0.26 fmol/ml (mean +/- SD). CONCLUSIONS: The present assay reliably measures ET-1 levels in rat and human plasma. It allows to discriminate between different forms of hypertension with high or low circulating levels of ET-1.

Seismic Wave Velocity as a Means of In-Place Density Measurement, Part 1, HR-114

Velocity-density tests conducted in the laboratory involved small 4-inch diameter by 4.58-inch-long compacted soil cylinders made up of 3 differing soil types and for varying degrees of density and moisture content, the latter being varied well beyond optimum moisture values. Seventeen specimens were tested, 9 with velocity determinations made along two elements of the cylinder, 180 degrees apart, and 8 along three elements, 120 degrees apart. Seismic energy was developed by blows of a small tack hammer on a 5/8-inch diameter steel ball placed at the center of the top of the cylinder, with the detector placed successively at four points spaced 1/2-inch apart on the side of the specimen involving wave travel paths varying from 3.36 inches to 4.66 inches in length. Time intervals were measured using a model 217 micro-seismic timer in both laboratory and field measurements. Forty blows of the hammer were required for each velocity determination, which amounted to 80 blows on 9 laboratory specimens and 120 blows on the remaining 8 cylinders. Thirty-five field tests were made over the three selected soil types, all fine-grained, using a 2-foot seismic line with hammer-impact points at 6-inch intervals. The small tack hammer and 5/8-inch steel ball was, again, used to develop seismic wave energy. Generally, the densities obtained from the velocity measurements were lower than those measured in the conventional field testing. Conclusions were reached that: (1) the method does not appear to be usable for measurement of density of essentially fine-grained soils when the moisture content greatly exceeds the optimum for compaction, and (2) due to a gradual reduction in velocity upon aging, apparently because of gradual absorption of pore water into the expandable interlayer region of the clay, the seismic test should be conducted immediately after soil compaction to obtain a meaningful velocity value.

Accuracy profile validation of a new analytical method for butane measurement using headspace-gas chromatography-mass spectrometry.

The aim of our study was to provide an innovative HS-GC/MS method applicable to the routine determination of butane concentration in forensic toxicology laboratories. The main drawback of the GC/MS methods discussed in literature concerning butane measurement was the absence of a specific butane internal standard necessary to perform quantification. Because no stable isotope of butane is commercially available, it is essential to develop a new approach by an in situ generation of standards. To avoid the manipulation of a stable isotope-labelled gas, we have chosen to generate in situ an internal labelled standard gas (C(4)H(9)D) following the basis of the stoichiometric formation of butane by the reaction of deuterated water (D(2)O) with Grignard reagent butylmagnesium chloride (C(4)H(9)MgCl). This method allows a precise measurement of butane concentration and therefore, a full validation by accuracy profile was presented.

Is sustainability certification for biochar the answer to environmental risks?

Biochar has the potential to make a major contribution to the mitigation of climate change, and enhancement of plant production. However, in order for biochar to fulfill this promise, the industry and regulating bodies must take steps to manage potential environmental threats and address negative perceptions. The potential threats to the sustainability of biochar systems, at each stage of the biochar life cycle, were reviewed. We propose that a sustainability framework for biochar could be adapted from existing frameworks developed for bioenergy. Sustainable land use policies, combined with effective regulation of biochar production facilities and incentives for efficient utilization of energy, and improved knowledge of biochar impacts on ecosystem health and productivity could provide a strong framework for the development of a robust sustainable biochar industry. Sustainability certification could be introduced to provide confidence to consumers that sustainable practices have been employed along the production chain, particularly where biochar is traded internationally.

Sustainability, certification, and regulation of biochar

Biochar has a relatively long half-life in soil and can fundamentally alter soil properties, processes, and ecosystem services. The prospect of global-scale biochar application to soils highlights the importance of a sophisticated and rigorous certification procedure. The objective of this work was to discuss the concept of integrating biochar properties with environmental and socioeconomic factors, in a sustainable biochar certification procedure that optimizes complementarity and compatibility between these factors over relevant time periods. Biochar effects and behavior should also be modelled at temporal scales similar to its expected functional lifetime in soils. Finally, when existing soil data are insufficient, soil sampling and analysis procedures need to be described as part of a biochar certification procedure.

How we experience immersive virtual environments: the concept of presence and its measurement

This paper reviews the concept of presence in immersive virtual environments, the sense of being there signalled by people acting and responding realistically to virtual situations and events. We argue that presence is a unique phenomenon that must be distinguished from the degree of engagement, involvement in the portrayed environment. We argue that there are three necessary conditions for presence: the (a) consistent low latency sensorimotor loop between sensory data and proprioception; (b) statistical plausibility: images must be statistically plausible in relation to the probability distribution of images over natural scenes. A constraint on this plausibility is the level of immersion;(c) behaviour-response correlations: Presence may be enhanced and maintained over time by appropriate correlations between the state and behaviour of participants and responses within the environment, correlations that show appropriate responses to the activity of the participants. We conclude with a discussion of methods for assessing whether presence occurs, and in particular recommend the approach of comparison with ground truth and give some examples of this.

Différences induites par la définition des périodes diurnes et nocturnes sur la pression artérielle et le dipping lors d'une mesure ambulatoire de la pression artérielle [Effects of nighttime and daytime interval definition on blood pressure and dipping in patients referred for ambulatory blood pressure measurement].

Ambulatory blood pressure monitoring (ABPM) has become indispensable for the diagnosis and control of hypertension. However, no consensus exists on how daytime and nighttime periods should be defined. OBJECTIVE: To compare daytime and nighttime blood pressure (BP) defined by an actigraph and by body position with BP resulting from arbitrary daytime and nighttime periods. PATIENTS AND METHOD: ABPM, sleeping periods and body position were recorded simultaneously using an actigraph (SenseWear Armband(®)) in patients referred for ABPM. BP results obtained with the actigraph (sleep and position) were compared to the results obtained with fixed daytime (7a.m.-10p.m.) and nighttime (10p.m.-7a.m.) periods. RESULTS: Data from 103 participants were available. More than half of them were taking antihypertensive drugs. Nocturnal BP was lower (systolic BP: 2.08±4.50mmHg; diastolic BP: 1.84±2.99mmHg, P<0.05) and dipping was more marked (systolic BP: 1.54±3.76%; diastolic BP: 2.27±3.48%, P<0.05) when nighttime was defined with the actigraph. Standing BP was higher (systolic BP 1.07±2.81mmHg; diastolic BP: 1.34±2.50mmHg) than daytime BP defined by a fixed period. CONCLUSION: Diurnal BP, nocturnal BP and dipping are influenced by the definition of daytime and nighttime periods. Studies evaluating the prognostic value of each method are needed to clarify which definition should be used.

Real-time quantitative PCR assay for measurement of bird telomeres

We present the application of a real-time quantitative PCR assay, previously developed to measure relative telomere length in humans and mice, to two bird species, the zebra finch Taeniopygia guttata and the Alpine swift Apus melba. This technique is based on the PCR amplification of telomeric (TTAGGG)(n) sequences using specific oligonucleotide primers. Relative telomere length is expressed as the ratio (T/S) of telomere repeat copy number (T) to control single gene copy number (S). This method is particularly useful for comparisons of individuals within species, or where the same individuals are followed longitudinally. We used glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as a single control gene. In both species, we validated our PCR measurements of relative telomere length against absolute measurements of telomere length determined by the conventional method of quantifying telomere terminal restriction fragment (TRF) lengths using both the traditional Southern blot analysis (Alpine swifts) and in gel hybridization (zebra finches). As found in humans and mice, telomere lengths in the same sample measured by TRF and PCR were well correlated in both the Alpine swift and the zebra finch.. Hence, this PCR assay for measurement of bird telomeres, which is fast and requires only small amounts of genomic DNA, should open new avenues in the study of environmental factors influencing variation in telomere length, and how this variation translates into variation in cellular and whole organism senescence.

Teaching, sustainability and environment in UPC buildings

Universities must motivate future professionals so that they are able to apply their experience over and beyond the scientific and technological context. These professionals should also be trained so that they are aware of the current position as regards the economy and limited energy resources, and they must be creative, knowledgeable and committed if they are to rethink the current model.The Departments of Architectural Technology II and Applied Physics, in collaboration with the Interdisciplinary Centre of Technology, Innovation and Education for Sustainability (CITIES), believed that students could be given the opportunity to specialise in the area of sustainable development by means of their final theses [2]. With this objective in mind, a line of theses called Energy Assessments was created as part of the Plan for Resource Consumption Efficiency (PECR). The line was based on a learning strategy that focused on the student.The teaching staff was able to observe that, in terms of cognitive aspects, the students improved their knowledge of environmental issues and the associated skills, and that they were more able to solve problems in the area of sustainability and had greater concerns about this subject matter after having completed their theses.

Methods for the analysis of two dimensional measurement data of paper web

This work is devoted to the problem of reconstructing the basis weight structure at paper web with black{box techniques. The data that is analyzed comes from a real paper machine and is collected by an o®-line scanner. The principal mathematical tool used in this work is Autoregressive Moving Average (ARMA) modelling. When coupled with the Discrete Fourier Transform (DFT), it gives a very flexible and interesting tool for analyzing properties of the paper web. Both ARMA and DFT are independently used to represent the given signal in a simplified version of our algorithm, but the final goal is to combine the two together. Ljung-Box Q-statistic lack-of-fit test combined with the Root Mean Squared Error coefficient gives a tool to separate significant signals from noise.