Warfarin anticoagulation in the perioperative period: is it safe?

A useful correlation between maximum thyroid uptake and radioiodine urine levels at different times after exposure was developed in order to determine when the intervention with an adequate blocking agent might still be effective. In an animal model (dog), six different doses were administered in the range of 100-600 kBq. The best correlation was found between the 125I uptake after 48 h (T-48) and urine radioactivity 4-6 h (U-4, U-5, U-6) after exposure. For the case of U-4, the equation Y(T-48) = 0.790 X(U-4) + 2.973 (r = 0.974 with a level of significance of p < 0.001) was obtained. An analogous study, carried out in humans (n = 20) to whom 1311 was administered, showed a similar correlation and level of significance: Y(T-24) = 1.162 X(U-4)+3.263 (r = 0.926; p < 0.001). The validity of this correlation was confirmed in four volunteers who received small doses of 125I(25-100 kBq), with good agreement between measured and extrapolated thyroid uptake and a mean difference of less than 10% (CV = 16.2%). Three different blocking agents were then tested in the same dog: potassium iodide, potassium perchlorate, and a thionamide (Tapazole). The blocking action of the first two compounds was about 90%, as opposed to only 48% for the third compound. Potassium iodide was chosen for its limited side effects and more universal utilization. The final study, carried out with four different doses, indicated that 25 mg of KI is the ideal amount to be administered to the dog. This corresponds to approximately 100 mg for a 70 kg human being (i.e., 1.4 mg kg(-1)). This dose, when administered to a volunteer 4 h after exposure, provided a thyroid blocking of 68%.     

A comparison of dimension reduction methods with application to multi-spectral images of sand used in concrete

This paper presents a comparison of dimension reduction methods based on a novel machine vision application for estimating moisture content in sand used to make concrete. For the application in question it is very important to know the moisture content of the sand so as to ensure good-quality concrete. In order to achieve a continuous in-line approach for the concrete mixing, digital image analysis is used. Multi-spectral images, consisting of nine spectral bands in the visible and near infrared (NIR) range, were acquired. Each image consists of approximately 9 million pixels. Five different sand types were examined with 20–60 images for each type. To reduce the amount of data, features were extracted from the multi-spectral images; the features were summary statistics on single bands and pairs of bands as well as morphological summaries. The number of features (2,016) is high in relation to the number of observations and, therefore, dimension reductive methods are needed. Furthermore, speed, which is an important consideration, is aided by the use of a small number of variables. On top of that, fewer dimensions tend to give more robust results. Two traditional statistical methods for dimension reduction (forward selection and principal components) combined with ordinary least squares and one sophisticated chemometrics algorithm (genetic algorithm-partial least squares) are compared to the recently proposed least angle regression-elastic net (LARS-EN) model selection method.     

Towards the effective tool wear control in micro-EDM milling

The electrode wear in micro-electrical discharge milling (micro-EDM milling) is one of the main problems to be solved in order to improve machining accuracy. This paper presents an investigation on wear and material removal in micro-EDM milling for selected process parameter combinations typical of rough and finish machining of micro-features in steel. The experiments were performed on state-of-the-art micro-EDM equipment. Based on discharge counting and volume measurements, electrode wear per discharge and material removal per discharge were measured for several energy levels. The influence of the accuracy of volume measurements on the electrode wear per discharge and on the material removal per discharge are discussed, and the issues limiting the applicability of real time wear sensing in micro-EDM milling are presented.     

Inventory centralization decision framework for spare parts

Within the current literature, there is a lack of a holistic and multidisciplinary approach to managing spare parts and their inventory configuration. This paper addresses this research gap by examining the key contextual factors which influence the degree of inventory centralization and proposes a novel holistic theoretical framework, the Inventory Centralization Decision Framework (ICDF), useful for practitioners. Through an extensive review of inventory management literature, six contextual factors influencing the degree of inventory centralization have been identified. Using the ICDF practitioners can assess the most advantageous inventory configuration of spare parts. The framework is tested on a large global company which, as a result, today actively uses the ICDF; thus showing its practical applicability.     

Proteasome Inhibitors with Photocontrolled Activity

Proteasome inhibitors are widely used in cancer treatment as chemotherapeutic agents. However, their employment often results in severe side effects, due to their non‐specific cytotoxicity towards healthy tissue. This problem might be overcome by using a photopharmacological approach, that is, by attaining external, dynamic, spatiotemporal photocontrol over the activity of a cytotoxic agent, achieved by the introduction of a photoswitchable moiety into its molecular structure. Here we describe the design, synthesis, and activity of photoswitchable proteasome inhibitors. Substantial differences in proteasome inhibitory activity in cell extracts were observed before and after irradiation with light. The presented results show potential for the development of chemotherapeutic agents that can be switched on and off with light, constituting a new strategy for spatiotemporally modulating proteasomal activity.     

Solid‐Phase Synthesis and Biological Evaluation of N‐Dipeptido L‐Homoserine Lactones as Quorum Sensing Activators

Bacteria use small signaling molecules to communicate in a process termed “quorum sensing” (QS), which enables the coordination of survival strategies, such as production of virulence factors and biofilm formation. In Gram‐negative bacteria, these signaling molecules are a series of N‐acylated L ‐homoserine lactones. With the goal of identifying non‐native compounds capable of modulating bacterial QS, a virtual library of N‐dipeptido L ‐homoserine lactones was screened in silico with two different crystal structures of LasR. The 30 most promising hits were synthesized on HMBA‐functionalized PEGA resin and released through an efficient acid‐mediated cyclative release mechanism. Subsequent screening for modulation of QS in Pseudomonas aeruginosa and E. coli identified six moderately strong activators. A follow‐up library designed from the preliminary derived structure–activity relationships was synthesized and evaluated for their ability to activate the QS system in this bacterium. This resulted in the identification of another six QS activators (two with low micromolar activity) thus illuminating structural features required for QS modulation.     

Unifying Solution and Surface Electrochemistry: Limitations and Opportunities in Surface Electrocatalysis

The electrochemical transformations involving small molecules could play a key role in energy storage and utilization. In this work, we develop a link between surface and solution electrochemistry and this is accomplished by relating the correlated binding of hydrogenated species on metal surfaces to their formation energy in solution. This link provides a semi-quantitative treatment of the thermodynamic landscape of multi-electron electrochemical reactions. Using this simple analysis, we identify some of the fundamental limits of oxygen, nitrogen and carbon electrochemistry. This analysis points to new avenues of electrocatalyst design and two such avenues are discussed in detail.     

Traditional and modern Greenlandic food - dietary composition, nutrients and contaminants

OBJECTIVES: High levels of n-3 fatty acids and other nutrients in traditional Inuit food appear to provide some protection against the typical diseases of affluent industrialized societies: cardiovascular diseases and type 2 diabetes. An increased intake of imported food among Inuits will probably increase their frequency of these diseases. However, since the 1970s it has become evident that the marine-based Inuit diet also contains high levels of potentially toxic lipophilic organic pollutants and heavy metals. Since these two food related opposing health effects appear to be inseparable, the phenomenon has been known as "The Arctic Dilemma". However, both the fatty acid composition and the contaminant levels vary in Greenlandic food items. Thus in principle it is possible to compose a diet where the benefits and risks are better balanced. Our objectives of this study were to compare traditional and modern meals in Greenland concerning the dietary composition, nutrients, and health indicators among the consumers. STUDY DESIGN: The present study was a cross-sectional dietary survey as part of the Arctic Monitoring and Assessment, Human Health Programme (AMAP). These results were compared with older dietary surveys in Greenland. METHODS: Dietary components, fatty acids, and nutrients in 90 local meals collected by duplicate portion method in Uummannaq town, north Greenland 2004 and in Narsaq, south Greenland 2006, were compared with 177 duplicate meals sampled in the village of Igdslorsuit, Uummannaq, district, 1976 and also compared with other dietary studies in Greenland 1953-1987. Anthropometric measures (weight, height, and body mass index, BMI) and blood lipids were measured as health indicators among the participants. RESULTS: Between the traditional foods sampled or analysed 30-50 years ago and the modern food from 2004 to 2006, significant differences were found in the dietary composition. The percentage of local food had decreased, to a present average of about 20% and with it the dietary content of n-3 fatty acids. Also, the intakes of many vitamins and minerals had decreased, and were below Nordic Nutrient Recommendations in 2004 and 2006. Vitamin A, B(1), (B(2)), B(12), iron, iodine, phosphorus, and selenium contents were correlated with n-3 content, whereas vitamin C, folate, and calcium contents were not and the same time very low. In the traditional food, especially from the villages, the intakes of vitamin A, vitamin D, and iron were extremely high and borderline toxic. The levels of contaminants such as organochlorins and heavy metals were also strongly correlated with the relative content of local food in the diet. The best balance between potentially beneficial and harmful substances was found for 20-30% local food, corresponding to a daily intake of 3-5 g of n-3 fatty acids. Body weight, height, body mass index (BMI), cholesterol, and S-triglycerides had increased significantly between 1976 and 2004. CONCLUSION: The dietary changes to a more western fare were found to be negative resulting in less adequate nutrient coverage but at the same time lower contaminant load. Thus, we recommend not to increase the consumption of local products beyond the present level but rather to improve the quality of the imported food.     

Hyphenating multisyringe flow injection lab-on-valve analysis with atomic fluorescence spectrometry for on-line bead injection preconcentration and determination of trace levels of hydride-forming elements in environmental samples

In this work the third generation of flow injection analysis, that is, the so-called micro-lab-on-valve (microLOV) approach, is proposed for the first time for the separation, preconcentration, and monitoring of metalloids as hyphenated with atomic fluorescence spectrometry (AFS). This was made feasible by interfacing the micromachined LOV-module with AFS by a multisyringe flowing stream network for on-line postcolumn derivatization of the eluate aimed at generation of hydride species. The potential of this new hyphenated technique for environmental assays was ascertained via determination of ultratrace level concentrations of total inorganic arsenic in freshwater. Employing quantitative preoxidation of As(III) to As(V) in the samples by means of permanganate, the method involves preconcentration of arsenate at pH 10 on a renewable anion exchanger, namely, Q-Sepharose, packed in a LOV microcolumn. The analyte species is afterward stripped out and concurrently prereduced by a 300 microL eluent plug containing 6 mol L(-)1 HCl and 10% KI. The eluate is downstream merged with a metered volume of sodium tetrahydroborate (0.3% w/v) for generation of arsine, which is subsequently quantified by AFS. The flow system facilitates on-column reduction of the retained arsenic with no need for application of programmable stopped flow. Yet, the high concentration of reductant and extreme pH conditions for elution hinder the sorbent to be reused due to gradual deactivation of the functional moieties, so that maximum benefit can be taken from the application of the bead renewable strategy. The proposed procedure is characterized by a high tolerance to metal species and interfering hydride-forming elements. In fact, ratios of Se(IV) to As < or = 5000 and Sb(V) to As < or = 500 are tolerated at the 10% interference level. Under the optimized experimental conditions, a detection limit (3sigma) of 0.02 ng mL(-1) As, a dynamic linear range of 0.05-2.0 ng mL(-1) As (by tailoring the AFS gain), an enrichment factor of 8.8 for arsenate, and a precision better than 6.0% at the 0.1 ng mL-1 level were obtained for the bead-injection mode whenever the loading sample volume was affixed at 3.0 mL. The reliability and accuracy of the automated procedure was ascertained by determining total inorganic arsenic in both spiked environmental waters and certified reference materials of variable matrix complexity (TMDA-54.3 and ERM-CA010) at the low ng mL(-1) level. No significant differences were found between the experimental results and the certified values at a significance level of 0.05.