Phenolic antioxidants in wood smoke

Ten prominent dimethoxyphenols were determined in birchwood smoke from choked and open laboratory burning and in chimney smoke from a tiled stove. The structures of the methoxyphenols are similar to those of the well-known tocopherol and ubiquinol antioxidants. The 2,6-dimethoxyphenols characterising hardwood smoke are stronger antioxidants than the corresponding 2-methoxyphenols present mainly in softwood smoke. The antioxidant activity is highest for the 2,6-dimethoxyphenols with 4-alkenyl and 4-alkyl groups, which constitute 60-70% of the total amount of dimethoxyphenols. Phenolic antioxidants are scavengers of oxygen radicals and should be considered when health hazards of small-scale incomplete biomass burning are estimated.     

Latency, activation, and binding proteins of TGF-beta

The TGF-beta superfamily of growth factors consists of an increasing number of different polypeptide modulators of cell growth, differentiation, and morphogenesis. Three mammalian isoforms have been molecularly cloned. Numerous ways to regulate the expression of the TGF-beta genes have been identified. TGF-betas are, for example, subject to regulation by retinoids, steroid hormones, and vitamin D. A characteristic feature in the biology of TGF-betas is that they are usually secreted from cells in latent forms. The large latent complex consists of the small latent complex (TGF-beta and its propeptide) and a high molecular weight protease resistant binding protein, latent TGF-beta binding protein (LTBP). LTBPs are required for the proper folding and secretion of TGF-beta. TGF-beta is not just secreted from cultured cells but is deposited via LTBPs to the pericellular space, namely to the extracellular matrix. Release of these complexes and activation by proteases is under tight regulation and provides a means to rapidly increase local concentrations of TGF-beta. Biological events, where enhanced or focal proteolysis and activation of latent TGF-beta takes place, include cell invasion, tissue remodeling, and wound healing.     

In situ polychlorophenol bioremediation potential of the indigenous bacterial community of boreal groundwater

The composition and chlorophenol-degrading potential of groundwater bacterial community in a permanently cold, oxygen-deficient chlorophenol contaminated aquifer at K?rk?l?, Finland was studied with the aim of evaluating in situ bioremediation potential. The groundwater contained from 10(4) to 10(7) microscopically counted cells/ml and up to 10(5) CFU/ml heterotrophic bacteria cultivable at 8 and 20 degrees C. Of the 102 pure cultures, of which 86% Gram-negative, from the plume area (10,000 microg of chlorophenols/l), 57% degraded 2, 3, 4, 6-tetrachlorophenol (TeCP), the main component of the wood preservative which was the source of contamination: 17% also degraded pentachlorophenol (PCP). The degraders were scattered among 16 different clusters of Gram-negatives mainly proteobacteria and members of Cytophaga/Flexibacter/Bacteroides phylum judged by the composition of whole-cell fatty acids. Only one Gram-positive degrading cluster was found containing seven actinobacteria closest to Nocardioides. Of the 88 pure cultures isolated from outside the plume (< 10 microg of chlorophenols/l) 67% were Gram-negative. Seven percent of the isolates degraded 2, 3. 4, 6-TeCP and/or PCP. Five of the Gram-positive isolates from outside the plume were Mycobacterium/Rhodococcus-related actinobacteria and O-methylated 2, 3, 4, 6-TeCP and PCP. The results show that chlorophenol degrading bacterial flora had been enriched as a result of contamination of the aquifer. This suggests significant in situ bioremediation potential of the site.     

Assessment of arterial blood flow characteristics in normal and atherosclerotic vessels with the fast Fourier flow method

The purpose of this study was to scrutinize the ability of magnetic resonance imaging (MRI)-performed measurements to compare arterial flow patterns in patients with peripheral arterial occlusive disease (PAOD), healthy volunteers (HV) and endurance athletes (EA). MRI blood flow data were partially repeated with Doppler ultrasound (DUS) with a view to a methodical comparison. Additionally, pulse wave velocity was assessed with the MUFF technique. For this purpose, MRI-performed flow measurements were performed in the common femoral artery in 21 patients with PAOD, in 34 HV and in 12 EA. The analysis included maximum flow velocities (MFV), velocity/time profile (VTP), pulse wave velocity (V _pulse), and vessel diameter (VD). In addition, MFV and VD were observed by DUS in most individuals. The results revealed a significant change regarding arterial blood flow characteristics in patients compared with HV and EA, with respect to the span between the peak positive and negative blood flow velocity in the femoral artery. The pulse wave velocity in patients was markedly elevated compared with healthy individuals. Furthermore, a complete, characteristic change in the VTP could be observed in patients. The methodical comparison between DUS and MRI showed a good correlation. Multi-slice Fourier flow data have indicated markedly increased pulse wave velocity in PAOD patients. Changes in the arterial blood flow can be clearly observed with MRI. In the future, this might offer a noninvasive possibility not only for the evaluation of the stage of the disease, but also for the detection of early, pre-clinical stages of atherosclerosis. This work was presented at the 1997 ISMRM Meeting, Vancouver, Canada and at the 14th Annual ESMRMB Meeting, Brussels, Belgium, 1997.     

The Mechanism of the Amorphous-to-Crystalline Transition in Ge2Sb2Te5 Ternary Alloys1

The kinetics of the amorphous-to-crystalline phase transformation in alloys with compositions around Ge₂Sb₂Te₅, used as erasable optical memories, was investigated by electric impedance, Raman spectroscopy, and optical and transmission electron microscopy. To induce the transformation, isothermal and isokinetic experiments were carried out at various temperatures and various heating rates. The results obtained agree with the Johnson–Mehl–Avrami model and show that the overall activation energy for the transition is about 8 eV, which exceeds previous estimations. The nucleation process changes during the transition and depends on both temperature and heating rate. The available data indicate that nuclei are formed both in the bulk and at the surface of crystallites, and that the structural details of the material (the crystallite size, in particular) depend greatly on the transformation conditions. Intercrystalline inclusions, which appear after the transition, contain Te precipitates within a structurally disordered phase. These inclusions have electrical and optical properties essentially different as compared to the rest of the sample; they could be residual phases formed due to the nonstoichiometric nature of the samples.     

A multi-criteria assessment tool for screening preliminary product platform concepts

Platform concept evaluation is a more challenging task than evaluating a single product concept since a platform must effectively support multiple product variants over a prolonged period of time. Existing platform methods develop specific criteria in depth, yet an evaluation of alternative platforms should be based on a broad set of criteria. Based on expert interviews, personal experience, and a literature search we propose a platform assessment tool consisting of 19 criteria for platform evaluation. The criteria are group into six categories: customer satisfaction, variety, after-sale, organization, flexibility, and complexity. The tool is focused on the early platform architecture phase, before proof-of-concept prototyping. However, it can also be used subsequently for platform refinement when more data becomes available. We demonstrate our platform assessment tool through an example with a cordless drill platform.     

A new generic scheme for functional logic programming with constraints

In this paper we propose a new generic scheme CFLP풟, intended as a logical and semantic framework for lazy Constraint Functional Logic Programming over a parametrically given constraint domain 풟. As in the case of the well known CLP풟 scheme for Constraint Logic Programming, 풟 is assumed to provide domain specific data values and constraints. CFLP풟 programs are presented as sets of constrained rewrite rules that define the behavior of possibly higher order and/or non-deterministic lazy functions over 풟. As a main novelty w.r.t. previous related work, we present a Constraint Rewriting Logic CRWL풟 which provides a declarative semantics for CFLP풟 programs. This logic relies on a new formalization of constraint domains and program interpretations, which allows a flexible combination of domain specific data values and user defined data constructors, as well as a functional view of constraints. This research has been partially supported by the Spanish National Projects MELODIAS (TIC2002-01167), MERIT-FORMS (TIN2005-09207-C03-03) and PROMESAS-CAM (S-0505/TIC/0407).