The potential for reductive dehalogenation of chlorinated phenol in a sulphidogenic environment inin situ enhanced biodegradation

An investigation of the reductive dechlorination of 2, 4, 6-trichlorophenol (2, 4, 6-TCP) under sulphate-reducing conditions was made. Sulphate-reducing and dechloro-respiring activities were studied in a mixed microbial population operated in batch-fed as well as continuous pine chip-packed fluidised bed reactors. Results showed that reductive dechlorination of 2, 4, 6-TCP by the dechloro-respiring bacteria may be indirectly stimulated by the fermentative activity of the sulphate-reducing population affected by sulphate and lactate concentrations. Sulphate was administered in excess (900 mg·ℓ-1) and limiting (110 mg·ℓ-1) concentrations. At these concentrations, SO42- was available in quantities sufficient and lower than that required to bring about consumption of lactate. Transformation to 2,4-dichlorophenol (2,4-DCP), 4-chlorophenol (4-CP) and phenol was enhanced in sulphate-limiting conditions with average 47.7% TCP reduction compared to 11.6% in sulphate-enriched administered reactors. The potential application requirements for dechlorination under sulphate-reducing conditions for in situ biodegradation are considered. The input electron donor: SO42- ratio is manipulated to effect accelerated dechlorination rates for chlorinated organic compound-contaminated soil/groundwater bioremediation applications where oxygen is frequently limited. Water SA Vol. 32(2) 2006: pp.243-24

Geroch--Kinnersley--Chitre group for Dilaton--Axion Gravity

Kinnersley--type representation is constructed for the four--dimensional Einstein--Maxwell--dilaton--axion system restricted to space--times possessing two non--null commuting Killing symmetries. New representation essentially uses the matrix--valued $SL(2,R)$ formulation and effectively reduces the construction of the Geroch group to the corresponding problem for the vacuum Einstein equations. An infinite hierarchy of potentials is introduced in terms of $2\times 2$ real symmetric matrices generalizing the scalar hierarchy of Kinnersley--Chitre known for the vacuum Einstein equations.Comment: Published in ``Quantum Field Theory under the Influence of External Conditions'', M. Bordag (Ed.) (Proc. of the International Workshop, Leipzig, Germany, 18--22 September 1995), B.G. Teubner Verlagsgessellschaft, Stuttgart--Leipzig, 1996, pp. 228-23

Giant Anharmonic Phonon Scattering in PbTe

Understanding the microscopic processes affecting the bulk thermal conductivity is crucial to develop more efficient thermoelectric materials. PbTe is currently one of the leading thermoelectric materials, largely thanks to its low thermal conductivity. However, the origin of this low thermal conductivity in a simple rocksalt structure has so far been elusive. Using a combination of inelastic neutron scattering measurements and first-principles computations of the phonons, we identify a strong anharmonic coupling between the ferroelectric transverse optic (TO) mode and the longitudinal acoustic (LA) modes in PbTe. This interaction extends over a large portion of reciprocal space, and directly affects the heat-carrying LA phonons. The LA-TO anharmonic coupling is likely to play a central role in explaining the low thermal conductivity of PbTe. The present results provide a microscopic picture of why many good thermoelectric materials are found near a lattice instability of the ferroelectric type

The Einstein-Vlasov sytem/Kinetic theory

The main purpose of this article is to guide the reader to theorems on global properties of solutions to the Einstein-Vlasov system. This system couples Einstein's equations to a kinetic matter model. Kinetic theory has been an important field of research during several decades where the main focus has been on nonrelativistic- and special relativistic physics, e.g. to model the dynamics of neutral gases, plasmas and Newtonian self-gravitating systems. In 1990 Rendall and Rein initiated a mathematical study of the Einstein-Vlasov system. Since then many theorems on global properties of solutions to this system have been established. The Vlasov equation describes matter phenomenologically and it should be stressed that most of the theorems presented in this article are not presently known for other such matter models (e.g. fluid models). The first part of this paper gives an introduction to kinetic theory in non-curved spacetimes and then the Einstein-Vlasov system is introduced. We believe that a good understanding of kinetic theory in non-curved spacetimes is fundamental in order to get a good comprehension of kinetic theory in general relativity.Comment: 31 pages. This article has been submitted to Living Rev. Relativity (http://www.livingreviews.org

A model for the compressible, viscoelastic behavior of human amnion addressing tissue variability through a single parameter

A viscoelastic, compressible model is proposed to rationalize the recently reported response of human amnion in multiaxial relaxation and creep experiments. The theory includes two viscoelastic contributions responsible for the short- and long-term time- dependent response of the material. These two contributions can be related to physical processes: water flow through the tissue and dissipative characteristics of the collagen fibers, respectively. An accurate agreement of the model with the mean tension and kinematic response of amnion in uniaxial relaxation tests was achieved. By variation of a single linear factor that accounts for the variability among tissue samples, the model provides very sound predictions not only of the uniaxial relaxation but also of the uniaxial creep and strip-biaxial relaxation behavior of individual samples. This suggests that a wide range of viscoelastic behaviors due to patient-specific variations in tissue composition

Identifying bereaved subjects at risk of complicated grief: Predictive value of questionnaire items in a cohort study

<p>Abstract</p> <p>Background</p> <p>Bereavement is a condition which most people experience several times during their lives. A small but noteworthy proportion of bereaved individuals experience a syndrome of prolonged psychological distress in relation to bereavement. The aim of the study was to develop a clinical tool to identify bereaved individuals who had a prognosis of complicated grief and to propose a model for a screening tool to identify those at risk of complicated grief applicable among bereaved patients in general practice and palliative care.</p> <p>Methods</p> <p>We examined the responses of 276 newly bereaved individuals to a variety of standardised and ad hoc questionnaire items eight weeks post loss. Inventory of Complicated Grief (ICG-R) was used as a gold standard of distress at six months after bereavement. Receiver operating characteristic (ROC) curves analysis was performed for all scales and items regarding ICG-R score. Sensitivity, specificity and area under curve (AUC) were calculated for scales and items with the most promising ROC curve analyses.</p> <p>Results</p> <p>Beck's Depression Inventory (BDI) was the scale with the highest AUC (0.83) and adding a single item question ('Even while my relative was dying, I felt a sense of purpose in my life') gave a sensitivity of 80% and specificity of 75%. The positive/negative predictive values for this combination of questions were 70% and 85%, respectively. With this screening tool bereaved people could be categorized into three groups where group 1 had 7%, group 2 had 23% and group 3 had 64% propensity of suffering from complicated grief six months post loss.</p> <p>Conclusions</p> <p>This study shows that the BDI in combination with a single item question eight weeks post loss may be used for clinical screening for risk of developing complicated grief after six months. The feasibility and clinical implications of the screening tool has to be tested in a clinical setting.</p

Theorems on existence and global dynamics for the Einstein equations

This article is a guide to theorems on existence and global dynamics of solutions of the Einstein equations. It draws attention to open questions in the field. The local-in-time Cauchy problem, which is relatively well understood, is surveyed. Global results for solutions with various types of symmetry are discussed. A selection of results from Newtonian theory and special relativity that offer useful comparisons is presented. Treatments of global results in the case of small data and results on constructing spacetimes with prescribed singularity structure or late-time asymptotics are given. A conjectural picture of the asymptotic behaviour of general cosmological solutions of the Einstein equations is built up. Some miscellaneous topics connected with the main theme are collected in a separate section.Comment: Submitted to Living Reviews in Relativity, major update of Living Rev. Rel. 5 (2002)

Gingival crevicular fluid MMP-8-concentrations in patients after acute myocardial infarction

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to determine the presence of matrix metalloproteinase-8 in the gingival crevicular fluid (GCF) of patients after acute myocardial infarction (AMI).</p> <p>Methods</p> <p>A total of 48 GCF samples from 20 AMI patients, hospitalized at the Department of Cardiology and Angiology of the Johannes Gutenberg University Mainz, were investigated. Besides the myocardial infarction all patients suffered from chronic periodontal disease. Fifty-one GCF samples from 20 healthy age matched individuals with similar periodontal conditions served as controls. The dental examination included the assessment of oral hygiene, gingival inflammation, probing pocket depth, clinical attachment level and X-ray examination. The study was only carried out after the positive consent of the regional ethic commission. A quantitative assessment of aMMP-8 levels in the gingival crevicular fluid was performed with the help of the DentoAnalyzer (Dentognostics GmbH, Jena, Germany), utilising an immunological procedure.</p> <p>Results</p> <p>The aMMP-8 concentrations found in the gingival crevicular fluid of the AMI patients significantly differed (p = 0.001; mean value 30.33 ± 41.99 ng/ml aMMP-8) from the control group (mean value 10.0 ± 10.7 ng/ml aMMP-8). These findings suggest that periodontal inflammation in AMI patients might be associated with higher MMP-8-values compared to the healthy controls.</p> <p>Conclusions</p> <p>The acute myocardial infarction seems to influence the degree of periodontal inflammation, thus the measurement of the gingival crevicular fluid MMP8 levels seems to be a helpful biochemical test to obtain information about the severity of the periodontal disease.</p

AMPA Receptor Activation Causes Silencing of AMPA Receptor-Mediated Synaptic Transmission in the Developing Hippocampus

Agonist-induced internalization of transmembrane receptors is a widespread biological phenomenon that also may serve as a mechanism for synaptic plasticity. Here we show that the agonist AMPA causes a depression of AMPA receptor (AMPAR) signaling at glutamate synapses in the CA1 region of the hippocampus in slices from developing, but not from mature, rats. This developmentally restricted agonist-induced synaptic depression is expressed as a total loss of AMPAR signaling, without affecting NMDA receptor (NMDAR) signaling, in a large proportion of the developing synapses, thus creating AMPAR silent synapses. The AMPA-induced AMPAR silencing is induced independently of activation of mGluRs and NMDARs, and it mimics and occludes stimulus-induced depression, suggesting that this latter form of synaptic plasticity is expressed as agonist-induced removal of AMPARs. Induction of long-term potentiation (LTP) rendered the developing synapses resistant to the AMPA-induced depression, indicating that LTP contributes to the maturation-related increased stability of these synapses. Our study shows that agonist binding to AMPARs is a sufficient triggering stimulus for the creation of AMPAR silent synapses at developing glutamate synapses