Obtaining a class of Type O pure radiation metrics with a cosmological constant, using invariant operators

Using the generalised invariant formalism we derive a class of conformally flat spacetimes whose Ricci tensor has a pure radiation and a Ricci scalar component. The method used is a development of the methods used earlier for pure radiation spacetimes of Petrov types O and N respectively. In this paper we demonstrate how to handle, in the generalised invariant formalism, spacetimes with isotropy freedom and rich Killing vector structure. Once the spacetimes have been constructed, it is straightforward to deduce their Karlhede classification: the Karlhede algorithm terminates at the fourth derivative order, and the spacetimes all have one degree of null isotropy and three, four or five Killing vectors.Comment: 29 page

Type O pure radiation metrics with a cosmological constant

In this paper we complete the integration of the conformally flat pure radiation spacetimes with a non-zero cosmological constant $\Lambda$, and $\tau \ne 0$, by considering the case $\Lambda +\tau\bar\tau \ne 0$. This is a further demonstration of the power and suitability of the generalised invariant formalism (GIF) for spacetimes where only one null direction is picked out by the Riemann tensor. For these spacetimes, the GIF picks out a second null direction, (from the second derivative of the Riemann tensor) and once this spinor has been identified the calculations are transferred to the simpler GHP formalism, where the tetrad and metric are determined. The whole class of conformally flat pure radiation spacetimes with a non-zero cosmological constant (those found in this paper, together with those found earlier for the case $\Lambda +\tau\bar\tau = 0$) have a rich variety of subclasses with zero, one, two, three, four or five Killing vectors

The Effectiveness of Grade 5 Mobilizations vs. Grade 1-4 Mobilizations on Mechanical Neck Pain: A Clinically Appraised Topic

• From 2000 to 2010, mechanical neck pain (MNP) prevalence ranged from 30% to 50% in adults. Other data suggests that 46% to 54% of every adult will experience some form of neck pain during their lives. • Non-thrust mobilizations (NTM) and Thrust mobilizations (TM) are among the common interventions used in manual therapy in treatment of MNP. • The evidence accumulated for this clinically appraised topic (CAT) suggests high clinical variability among the effectiveness in NTM and TM among adults with mechanical neck pain

Effects of Glutamate Receptor Agonists on the P13 Auditory Evoked Potential and Startle Response in the Rat

The P13 potential is the rodent equivalent of the P50 potential, which is an evoked response recorded at the vertex (Vx) 50 ms following an auditory stimulus in humans. Both the P13 and P50 potentials are only present during waking and rapid eye movement (REM) sleep, and are considered to be measures of level of arousal. The source of the P13 and P50 potentials appears to be the pedunculopontine nucleus (PPN), a brainstem nucleus with indirect ascending projections to the cortex through the intralaminar thalamus, mediating arousal, and descending inhibitory projections to the caudal pontine reticular formation (CPRF), which mediates the auditory startle response (SR). We tested the hypothesis that intracranial microinjection (ICM) of glutamate (GLU) or GLU receptor agonists will increase the activity of PPN neurons, resulting in an increased P13 potential response, and decreased SR due to inhibitory projections from the PPN to the CPRF, in freely moving animals. Cannulae were inserted into the PPN to inject neuroactive agents, screws were inserted into the Vx in order to record the P13 potential, and electrodes inserted into the dorsal nuchal muscle to record electromyograms and SR amplitude. Our results showed that ICM of GLU into the PPN dose-dependently increased the amplitude of the P13 potential and decreased the amplitude of the SR. Similarly, ICM of N-methyl-d-aspartic acid or kainate into the PPN increased the amplitude of the P13 potential. These findings indicate that glutamatergic input to the PPN plays a role in arousal control in vivo, and changes in glutamatergic input, or excitability of PPN neurons, could be implicated in a number of neuropsychiatric disorders with the common symptoms of hyperarousal and REM sleep dysregulation

Gamma band activity in the developing parafascicular nucleus

The parafascicular nucleus (Pf) receives cholinergic input from the pedunculopontine nucleus, part of the reticular activating system involved in waking and rapid eye movement (REM) sleep, and sends projections to the cortex. We tested the hypothesis that Pf neurons fire maximally at gamma band frequency (30–90 Hz), that this mechanism involves high-threshold voltage-dependent P/Q- and N-type calcium channels, and that this activity is enhanced by the cholinergic agonist carbachol (CAR). Patch-clamped 9- to 25-day-old rat Pf neurons (n = 299) manifested a firing frequency plateau at gamma band when maximally activated (31.5 ± 1.5 Hz) and showed gamma oscillations when voltage-clamped at holding potentials above −20 mV, and the frequency of the oscillations increased significantly with age (24.6 ± 3.8 vs. 51.6 ± 4.4 Hz, P < 0.001) but plateaued at gamma frequencies. Cells exposed to CAR showed significantly higher frequencies early in development compared with those without CAR (24.6 ± 3.8 vs. 41.7 ± 4.3 Hz, P < 0.001) but plateaued with age. The P/Q-type calcium channel blocker ω-agatoxin-IVA (ω-Aga) blocked gamma oscillations, whereas the N-type blocker ω-conotoxin-GVIA (ω-CgTx) only partially decreased the power spectrum amplitude of gamma oscillations. The blocking effect of ω-Aga on P/Q-type currents and ω-CgTx on N-type currents was consistent over age. We conclude that P/Q- and N-type calcium channels appear to mediate Pf gamma oscillations during development. We hypothesize that the cholinergic input to the Pf could activate these cells to oscillate at gamma frequency, and perhaps relay these rhythms to cortical areas, thus providing a stable high-frequency state for “nonspecific” thalamocortical processing.Fil: Kezunovic, Nebojsa. University Of Arkansas For Medical Sciences; Estados UnidosFil: Hyde, James. University Of Arkansas For Medical Sciences; Estados UnidosFil: Simon, Christen. University Of Arkansas For Medical Sciences; Estados UnidosFil: Urbano Suarez, Francisco Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Williams, D. Keith. University Of Arkansas For Medical Sciences; Estados UnidosFil: Garcia Rill, Edgar. University Of Arkansas For Medical Sciences; Estados Unido

Proteomic measures of gamma oscillations

Background: Gamma oscillations serve complex processes, and the first stage of their generation is the reticular activating system (RAS), which mediates the gamma-activity states of waking and paradoxical sleep. We studied whether the pedunculopontine nucleus (PPN), part of the RAS in which every cell manifests intrinsic gamma oscillations, undergoes changes resulting in distinctive protein expression. New method: We previously found that a histone deacetylation inhibitor, trichostatin A (TSA), acutely (30 min) blocked these oscillations. We developed a proteomic method for sampling stimulated and unstimulated PPN and determining protein expression in 1 mm punches of tissue from brain slices subjected to various treatments. Results: We compared brain slices exposed for 30 min to TSA (unstimulated), to the cholinergic agonist carbachol (CAR), known to induce PPN gamma oscillations, or exposed to both TSA + CAR. Comparison with existing methods: Label-free proteomics provides an unbiased and sensitive method to detect protein changes in the PPN. Our approach is superior to antibody-based methods that can lack specificity and can only be done for known targets. Proteomics methods like these have been leveraged to study molecular pathways in numerous systems and disease states. Conclusions: Significant protein changes were seen in two functions essential to the physiology of the PPN: cytoskeletal and intracellular [Ca2+] regulation proteins. TSA decreased, while CAR increased, and TSA + CAR had intermediate effects, on expression of these proteins. These results support the feasibility of the methods developed for determining proteomic changes in small samples of tissue participating in the most complex of brain processes.Fil: Byrum, Stephanie D.. Arkansas Children's Research Institute; Estados UnidosFil: Washam, Charity L.. Arkansas Children's Research Institute; Estados UnidosFil: Tackett, Alan J.. Arkansas Children's Research Institute; Estados UnidosFil: Garcia Rill, Edgar. University of Arkansas for Medical Sciences; Estados UnidosFil: Bisagno, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; ArgentinaFil: Urbano Suarez, Francisco Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentin

Cholinergic modulation of the sleep state-dependent P13 midlatency auditory evoked potential in the rat

Abstract Injections into the pedunculopontine nucleus (PPN) of the cholinergic receptor agonist, carbachol (CAR), were found to reduce the amplitude of the vertex-recorded, sleep state-dependent P13 midlatency evoked potential in a dose-and time-dependent manner. This effect was blocked or reduced by pretreatment with the muscarinic receptor antagonist, scopolamine, injected into the PPN. © 2000 Elsevier Science B. V. All rights reserved. . The present characteristics of this potential in both species are (1) sleep study was conducted to determine if injections of a state-dependence (it is present during waking and paradoxcholinergic (muscarinic receptor) agonist into the region of ical sleep, but absent during slow wave sleep, i.e. during the PPN would affect the manifestation of the vertexstates of cortical EEG synchronization of high frequencies recorded P13 potential, and whether or not such an effect but absent during synchronization of low frequencies), skull. Guide cannulae were implanted stereotaxically 2 mm Cholinergic mesopontine neurons of the PPN are also dorsal to the PPN (A: 1.0, L: 1.9, H: 3.0

EcID. A database for the inference of functional interactions in E. coli

The EcID database (Escherichia coli Interaction Database) provides a framework for the integration of information on functional interactions extracted from the following sources: EcoCyc (metabolic pathways, protein complexes and regulatory information), KEGG (metabolic pathways), MINT and IntAct (protein interactions). It also includes information on protein complexes from the two E. coli high-throughput pull-down experiments and potential interactions extracted from the literature using the web services associated to the iHOP text-mining system. Additionally, EcID incorporates results of various prediction methods, including two protein interaction prediction methods based on genomic information (Phylogenetic Profiles and Gene Neighbourhoods) and three methods based on the analysis of co-evolution (Mirror Tree, In Silico 2 Hybrid and Context Mirror). EcID associates to each prediction a specifically developed confidence score. The two main features that make EcID different from other systems are the combination of co-evolution-based predictions with the experimental data, and the introduction of E. coli-specific information, such as gene regulation information from EcoCyc. The possibilities offered by the combination of the EcID database information are illustrated with a prediction of potential functions for a group of poorly characterized genes related to yeaG. EcID is available online at http://ecid.bioinfo.cnio.es

EcID. A database for the inference of functional interactions in E. coli

The EcID database (Escherichia coli Interaction Database) provides a framework for the integration of information on functional interactions extracted from the following sources: EcoCyc (metabolic pathways, protein complexes and regulatory information), KEGG (metabolic pathways), MINT and IntAct (protein interactions). It also includes information on protein complexes from the two E. coli high-throughput pull-down experiments and potential interactions extracted from the literature using the web services associated to the iHOP text-mining system. Additionally, EcID incorporates results of various prediction methods, including two protein interaction prediction methods based on genomic information (Phylogenetic Profiles and Gene Neighbourhoods) and three methods based on the analysis of co-evolution (Mirror Tree, In Silico 2 Hybrid and Context Mirror). EcID associates to each prediction a specifically developed confidence score. The two main features that make EcID different from other systems are the combination of co-evolution-based predictions with the experimental data, and the introduction of E. coli-specific information, such as gene regulation information from EcoCyc. The possibilities offered by the combination of the EcID database information are illustrated with a prediction of potential functions for a group of poorly characterized genes related to yeaG. EcID is available online at http://ecid.bioinfo.cnio.es

Tuneable 3D printed bioreactors for transaminations under continuous-flow

A method to efficiently immobilize enzymes on 3D printed continuous-flow devices is presented. Application of these chemically modified devices enables rapid screening of immobilization mechanisms and reaction conditions, simple transfer of optimised conditions into tailored printed microfluidic reactors and development of continuous-flow biocatalytic processes. The bioreactors showed good activity (8-20.5 μmol h⁻¹ mgenz⁻¹) in the kinetic resolution of 1-methylbenzylamine, and very good stability (ca. 100 h under flow)