Advances of dual source, dual-energy imaging in postmortem CT

This paper focuses on the use of multi-detector row dual-energy computed tomography (DECT) in the evaluation of postmortal examinations. The use of dual energy moves postmortem CT to an entirely new dimension of diagnostic sensitivity where contrast in the image is not merely limited to X-ray attenuation differences, but may include elements of functional and tissue characterization. This additional information may be used to improve the benefit postmortem imaging can provide to supplement and simplify the conventional autopsy.

CD39 is incorporated into plasma microparticles where it maintains functional properties and impacts endothelial activation

Plasma microparticles (MPs, <1.5 mum) originate from platelet and cell membrane lipid rafts and possibly regulate inflammatory responses and thrombogenesis. These actions are mediated through their phospholipid-rich surfaces and associated cell-derived surface molecules. The ectonucleotidase CD39/ecto-nucleoside triphosphate diphosphohydrolase1 (E-NTPDase1) modulates purinergic signalling through pericellular ATP and ADP phosphohydrolysis and is localized within lipid rafts in the membranes of endothelial- and immune cells. This study aimed to determine whether CD39 associates with circulating MPs and might further impact phenotype and function. Plasma MPs were found to express CD39 and exhibited classic E-NTPDase ecto-enzymatic activity. Entpd1 (Cd39) deletion in mice produced a pro-inflammatory phenotype associated with quantitative and qualitative differences in the MP populations, as determined by two dimensional-gel electrophoresis, western blot and flow cytometry. Entpd1-null MPs were also more abundant, had significantly higher proportions of platelet- and endothelial-derived elements and decreased levels of interleukin-10, tumour necrosis factor receptor 1 and matrix metalloproteinase 2. Consequently, Cd39-null MP augment endothelial activation, as determined by inflammatory cytokine release and upregulation of adhesion molecules in vitro. In conclusion, CD39 associates with circulating MP and may directly or indirectly confer functional properties. Our data also suggest a modulatory role for CD39 within MP in the exchange of regulatory signals between leucocytes and vascular cells.

DENSITY OF AMORPHOUS CARBON BY USING DENSITY FUNCTIONAL THEORY

Amorphous carbon has been investigated for a long time. Since it has the random orientation of carbon atoms, its density depends on the position of each carbon atom. It is important to know the density of amorphous carbon to use it for modeling advance carbon materials in the future. Two methods were used to create the initial structures of amorphous carbon. One is the random placement method by randomly locating 100 carbon atoms in a cubic lattice. Another method is the liquid-quench method by using reactive force field (ReaxFF) to rapidly decrease the system of 100 carbon atoms from the melting temperature. Density functional theory (DFT) was used to refine the position of each carbon atom and the dimensions of the boundaries to minimize the ground energy of the structure. The average densities of amorphous carbon structures created by the random placement method and the liquid-quench method are 2.59 and 2.44 g/cm3, respectively. Both densities have a good agreement with previous works. In addition, the final structure of amorphous carbon generated by the liquid-quench method has lower energy.

EXTRACTION OF PICTORIAL ENERGY INFORMATION FROM CAMPUS UNMETERED BUILDINGS USING IMAGE PROCESSING TECHNIQUES

In recent years, advanced metering infrastructure (AMI) has been the main research focus due to the traditional power grid has been restricted to meet development requirements. There has been an ongoing effort to increase the number of AMI devices that provide real-time data readings to improve system observability. Deployed AMI across distribution secondary networks provides load and consumption information for individual households which can improve grid management. Significant upgrade costs associated with retrofitting existing meters with network-capable sensing can be made more economical by using image processing methods to extract usage information from images of the existing meters. This thesis presents a new solution that uses online data exchange of power consumption information to a cloud server without modifying the existing electromechanical analog meters. In this framework, application of a systematic approach to extract energy data from images replaces the manual reading process. One case study illustrates the digital imaging approach is compared to the averages determined by visual readings over a one-month period.

Long-term gas exchange characteristics as marker of deterioration in patients with cystic fibrosis

Background and Aim In patients with cystic fibrosis (CF) the architecture of the developing lungs and the ventilation of lung units are progressively affected, influencing intrapulmonary gas mixing and gas exchange. We examined the long-term course of blood gas measurements in relation to characteristics of lung function and the influence of different CFTR genotype upon this process. Methods Serial annual measurements of PaO2 and PaCO2 assessed in relation to lung function, providing functional residual capacity (FRCpleth), lung clearance index (LCI), trapped gas (VTG), airway resistance (sReff), and forced expiratory indices (FEV1, FEF50), were collected in 178 children (88 males; 90 females) with CF, over an age range of 5 to 18 years. Linear mixed model analysis and binary logistic regression analysis were used to define predominant lung function parameters influencing oxygenation and carbon dioxide elimination. Results PaO2 decreased linearly from age 5 to 18 years, and was mainly associated with FRCpleth, (p < 0.0001), FEV1 (p < 0.001), FEF50 (p < 0.002), and LCI (p < 0.002), indicating that oxygenation was associated with the degree of pulmonary hyperinflation, ventilation inhomogeneities and impeded airway function. PaCO2 showed a transitory phase of low PaCO2 values, mainly during the age range of 5 to 12 years. Both PaO2 and PaCO2 presented with different progression slopes within specific CFTR genotypes. Conclusion In the long-term evaluation of gas exchange characteristics, an association with different lung function patterns was found and was closely related to specific genotypes. Early examination of blood gases may reveal hypocarbia, presumably reflecting compensatory mechanisms to improve oxygenation.

Aufbau hochfunktionaler Intralogistik-Knoten mittels kleinskaliger Module als Cognitive Conveyor

Kleinskalige, multifunktionale Module haben ein hohes Potential bei der wirtschaftlichen und flexiblen Gestaltung intralogistischer Systeme mit hoher Funktionalität. Durch dezentrale Steuerung und eigener Intelligenz der Module ist das System frei skalierbar und der Installationsaufwand wird minimiert. Mittels eines neuartigen Konzeptes der Datenkommunikation für Stetigförderer erfolgt der Informationsaustausch drahtlos mit Hilfe optoelektrischer Elemente. Die Kleinskaligkeit der Transportmodule gegenüber der Transporteinheit im Zusammenhang mit dem Steuerungskonzept erlaubt eine selektive Beschaltung der Module nach Bedarf und damit eine optimierte Energieausnutzung im Betrieb. Prototypen auf Basis von Schwenkrollen mit integrierter Antriebstechnik und Steuerung lassen das Potential des Prinzips erkennen. Das neu entwickelte Konzept der Schrägscheibe hilft bei der anspruchsvollen Integration der Antriebstechnik in das Modul durch das Prinzip der koaxialen Aktoren. Durch omnidirektionalen Funktionsumfang der Module entsteht im Zusammenschluss zu einer Modulmatrix ein hochflexibel einsetzbares Intralogistik-Modul. Die Vernetzung dieser hochfunktionalen Knoten durch einfache Fördertechnik bietet die Möglichkeit einfacher Planung flexibler Logistiksysteme.

SOLAR RADIATION PRESSURE AND LOCAL INTERSTELLAR MEDIUM FLOW PARAMETERS FROM INTERSTELLAR BOUNDARY EXPLORER LOW ENERGY HYDROGEN MEASUREMENTS

Neutral hydrogen atoms that travel into the heliosphere from the local interstellar medium (LISM) experience strong effects due to charge exchange and radiation pressure from resonant absorption and re-emission of Lyα. The radiation pressure roughly compensates for the solar gravity. As a result, interstellar hydrogen atoms move along trajectories that are quite different than those of heavier interstellar species such as helium and oxygen, which experience relatively weak radiation pressure. Charge exchange leads to the loss of primary neutrals from the LISM and the addition of new secondary neutrals from the heliosheath. IBEX observations show clear effects of radiation pressure in a large longitudinal shift in the peak of interstellar hydrogen compared with that of interstellar helium. Here, we compare results from the Lee et al. interstellar neutral model with IBEX-Lo hydrogen observations to describe the distribution of hydrogen near 1 AU and provide new estimates of the solar radiation pressure. We find over the period analyzed from 2009 to 2011 that radiation pressure divided by the gravitational force (μ) has increased slightly from μ = 0.94 ± 0.04 in 2009 to μ = 1.01 ± 0.05 in 2011. We have also derived the speed, temperature, source longitude, and latitude of the neutral H atoms and find that these parameters are roughly consistent with those of interstellar He, particularly when considering the filtration effects that act on H in the outer heliosheath. Thus, our analysis shows that over the period from 2009 to 2011, we observe signatures of neutral H consistent with the primary distribution of atoms from the LISM and a radiation pressure that increases in the early rise of solar activity.

AMPA RECEPTOR ALLOSTERISM: MEASUREMENT OF THE CONFORMATIONAL CHANGES IN THE LIGAND BINDING DOMAIN OF A FUNCTIONAL RECEPTOR

Ionotropic glutamate receptors are important excitatory neurotransmitter receptors in the mammalian central nervous system that have been implicated in a number of neuropathologies such as epilepsy, ischemia, and amyotrophic lateral sclerosis. Glutamate binding to an extracellular ligand binding domain initiates a series of structural changes that leads to the formation of a cation selective transmembrane channel, which consequently closes due to desensitization of the receptor. The crystal structures of the AMPA subtype of the glutamate receptor have been particularly useful in providing initial insight into the conformational changes in the ligand binding domain; however, these structures are limited by crystallographic constraint. To gain a clear picture of how agonist binding is coupled to channel activation and desensitization, it is essential to study changes in the ligand binding domain in a dynamic, physiological state. In this dissertation, a technique called Luminescence Resonance Energy Transfer was used to determine the conformational changes associated with activation and desensitization in a functional AMPA receptor (ÄN*-AMPA) that contains the ligand binding domain and transmembrane segments; ÄN*-AMPA has been modified such that fluorophores can be introduced at specific sites to serve as a readout of cleft closure or to establish intersubunit distances. Previous structural studies of cleft closure of the isolated ligand binding domain in conjunction with functional studies of the full receptor suggest that extent of cleft closure correlates with extent of activation. Here, LRET has been used to show that a similar relationship between cleft closure and activation is observed in the “full length” receptor showing that the isolated ligand binding domain is a good model of the domain in the full length receptor for changes within a subunit. Similar LRET investigations were used to study intersubunit distances specifically to probe conformational changes between subunits within a dimer in the tetrameric receptor. These studies show that the dimer interface is coupled in the open state, and decoupled in the desensitized state, similar to the isolated ligand binding domain crystal structure studies. However, we show that the apo state dimer interface is not pre-formed as in the crystal structure, hence suggesting a mechanism for functional transitions within the receptor based on LRET distances obtained.

Characterization of Hsp70 binding and nucleotide exchange by the yeast Hsp110 chaperone Sse1.

SSE1 and SSE2 encode the essential yeast members of the Hsp70-related Hsp110 molecular chaperone family. Both mammalian Hsp110 and the Sse proteins functionally interact with cognate cytosolic Hsp70s as nucleotide exchange factors. We demonstrate here that Sse1 forms high-affinity (Kd approximately 10-8 M) heterodimeric complexes with both yeast Ssa and mammalian Hsp70 chaperones and that binding of ATP to Sse1 is required for binding to Hsp70s. Sse1.Hsp70 heterodimerization confers resistance to exogenously added protease, indicative of conformational changes in Sse1 resulting in a more compact structure. The nucleotide binding domains of both Sse1/2 and the Hsp70s dictate interaction specificity and are sufficient for mediating heterodimerization with no discernible contribution from the peptide binding domains. In support of a strongly conserved functional interaction between Hsp110 and Hsp70, Sse1 is shown to associate with and promote nucleotide exchange on human Hsp70. Nucleotide exchange activity by Sse1 is physiologically significant, as deletion of both SSE1 and the Ssa ATPase stimulatory protein YDJ1 is synthetically lethal. The Hsp110 family must therefore be considered an essential component of Hsp70 chaperone biology in the eukaryotic cell.

Physical and functional interaction between the dopamine transporter and the synaptic vesicle protein synaptogyrin-3.

Uptake through the dopamine transporter (DAT) represents the primary mechanism used to terminate dopaminergic transmission in brain. Although it is well known that dopamine (DA) taken up by the transporter is used to replenish synaptic vesicle stores for subsequent release, the molecular details of this mechanism are not completely understood. Here, we identified the synaptic vesicle protein synaptogyrin-3 as a DAT interacting protein using the split ubiquitin system. This interaction was confirmed through coimmunoprecipitation experiments using heterologous cell lines and mouse brain. DAT and synaptogyrin-3 colocalized at presynaptic terminals from mouse striatum. Using fluorescence resonance energy transfer microscopy, we show that both proteins interact in live neurons. Pull-down assays with GST (glutathione S-transferase) proteins revealed that the cytoplasmic N termini of both DAT and synaptogyrin-3 are sufficient for this interaction. Furthermore, the N terminus of DAT is capable of binding purified synaptic vesicles from brain tissue. Functional assays revealed that synaptogyrin-3 expression correlated with DAT activity in PC12 and MN9D cells, but not in the non-neuronal HEK-293 cells. These changes were not attributed to changes in transporter cell surface levels or to direct effect of the protein-protein interaction. Instead, the synaptogyrin-3 effect on DAT activity was abolished in the presence of the vesicular monoamine transporter-2 (VMAT2) inhibitor reserpine, suggesting a dependence on the vesicular DA storage system. Finally, we provide evidence for a biochemical complex involving DAT, synaptogyrin-3, and VMAT2. Collectively, our data identify a novel interaction between DAT and synaptogyrin-3 and suggest a physical and functional link between DAT and the vesicular DA system.

Functional analysis of the amine substrate specificity domain of pepper tyramine and serotonin N-hydroxycinnamoyltransferases.

Pepper (Capsicum annuum) serotonin N-hydroxycinnamoyltransferase (SHT) catalyzes the synthesis of N-hydroxycinnamic acid amides of serotonin, including feruloylserotonin and p-coumaroylserotonin. To elucidate the domain or the key amino acid that determines the amine substrate specificity, we isolated a tyramine N-hydroxycinnamoyltransferase (THT) gene from pepper. Purified recombinant THT protein catalyzed the synthesis of N-hydroxycinnamic acid amides of tyramine, including feruloyltyramine and p-coumaroyltyramine, but did not accept serotonin as a substrate. Both the SHT and THT mRNAs were found to be expressed constitutively in all pepper organs. Pepper SHT and THT, which have primary sequences that are 78% identical, were used as models to investigate the structural determinants responsible for their distinct substrate specificities and other enzymatic properties. A series of chimeric genes was constructed by reciprocal exchange of DNA segments between the SHT and THT cDNAs. Functional characterization of the recombinant chimeric proteins revealed that the amino acid residues 129 to 165 of SHT and the corresponding residues 125 to 160 in THT are critical structural determinants for amine substrate specificity. Several amino acids are strongly implicated in the determination of amine substrate specificity, in which glycine-158 is involved in catalysis and amine substrate binding and tyrosine-149 plays a pivotal role in controlling amine substrate specificity between serotonin and tyramine in SHT. Furthermore, the indisputable role of tyrosine is corroborated by the THT-F145Y mutant that uses serotonin as the acyl acceptor. The results from the chimeras and the kinetic measurements will direct the creation of additional novel N-hydroxycinnamoyltransferases from the various N-hydroxycinnamoyltransferases found in nature.

STUDIES ON ENERGY METABOLISM IN THE HIPPOCAMPUS AFTER ISCHEMIA

The gerbil model of ischemia was used to determine the effect of carotid occlusion on energy metabolites in cellular layers of discrete regions of the hippocampus and dentate gyrus. Levels of glucose, glycogen, ATP and phosphocreatine (PCr) were unchanged after 1 minute of ischemia. However, 3 minutes of ischemia produced a dramatic decrease in net levels of all metabolites. No additional decrease was observed after 15 minutes of ischemia. Re-establishment of the blood flow for 5 minutes after a 15 minute ischemic episode returned all metabolites to pre-ischemia levels. Concentrations of glucose and glycogen were elevated in sham-operated animals as a function of the pentobarbital anesthetic employed. In other studies, elevated GABA levels (produced by inhibiting GABA-transaminase with (gamma)-vinyl-GABA (GVG)) were found to decrease the rate of utilization of the high-energy phosphate metabolites ATP and PCr in the mouse cortex. In addition, glucose and glycogen levels were increased. Thus, tonic inhibition by GABA produced decreased cellular activity. Additional experiments demonstrated the attenuation of ischemia-induced metabolite depletion in cellular layers of regions of the hippocampus, dentate gyrus and cortex after GVG administration. Under ether, 1 minute of bilateral carotid occlusion produced a dramatic decrease in metabolite levels. After GVG treatment, the decrease was blocked completely for glucose, glycogen and ATP, and partially for PCr. Therefore, GABA-transaminase inhibition produced increased levels of GABA which subsequently decreased cellular activity. The protection against ischemia may have been due to (a)decreased metabolic rate; the available energy stores were utilized at a slower rate, and (b)increased levels of energy substrates; additional supplies available to maintain viability. These data suggest that the functional state of neural tissue can determine the response to metabolic stress. ^

Functional wiring of hypocretin and LC-NE neurons: implications for arousal.

To survive in a rapidly changing environment, animals must sense their external world and internal physiological state and properly regulate levels of arousal. Levels of arousal that are abnormally high may result in inefficient use of internal energy stores and unfocused attention to salient environmental stimuli. Alternatively, levels of arousal that are abnormally low may result in the inability to properly seek food, water, sexual partners, and other factors necessary for life. In the brain, neurons that express hypocretin neuropeptides may be uniquely posed to sense the external and internal state of the animal and tune arousal state according to behavioral needs. In recent years, we have applied temporally precise optogenetic techniques to study the role of these neurons and their downstream connections in regulating arousal. In particular, we have found that noradrenergic neurons in the brainstem locus coeruleus (LC) are particularly important for mediating the effects of hypocretin neurons on arousal. Here, we discuss our recent results and consider the implications of the anatomical connectivity of these neurons in regulating the arousal state of an organism across various states of sleep and wakefulness.

Psychological Data from an Exploration of the Rapport / Synchrony Interplay Using Motion Energy Analysis

These data result from an investigation examining the interplay between dyadic rapport and consequential behavior-mirroring. Participants responded to a variety of interpersonally-focused pretest measures prior to their engagement in videotaped interdependent tasks (coded for interactional synchrony using Motion Energy Analysis [17,18]). A post-task evaluation of rapport and other related constructs followed each exchange. Four studies shared these same dependent measures, but asked distinct questions: Study 1 (Ndyad = 38) explored the influence of perceived responsibility and gender-specificity of the task; Study 2 (Ndyad = 51) focused on dyad sex-makeup; Studies 3 (Ndyad = 41) and 4 (Ndyad = 63) examined cognitive load impacts on the interactions. Versions of the data are structured with both individual and dyad as the unit of analysis. Our data possess strong reuse potential for theorists interested in dyadic processes and are especially pertinent to questions about dyad agreement and interpersonal perception / behavior association relationships.

Functional proteomics and biochemsitry: working together to unravel mitochondrial phenomena of African trypansomes

Eukaryotic cells are compartmentalized into membrane-bound organelles in order to provide sheltered reaction rooms for various specific processes. Organelles are not randomly distributed in a cell or operate isolated from each other. At the contrary — some organelles are closely linked and their functions are tightly orchestrated. The most well-known example of two such organelles acting in concert are the ER and the mitochondrion that work together in order to coordinate cellular lipid biosynthesis, maintain Ca2+-homeostasis, regulate mitochondrial division and control mitochondrial/ER shape as well as to synchronize the movement of these organelles within a cell. To study the mitochondrion and its interface to the ER requires a simplified mitochondrial system. African trypanosomes represent such a system. The unicellular parasite that causes devastating diseases in humans and animals has only one large mitochondrion that does not undergo fission/fusion events except for the context of cell division. Moreover, mitochondrial functions and morphology are highly regulated throughout the life cycle of the protozoan. Central to the understanding of how mitochondria control their morphology, communicate with their surroundings and manage exchange of metabolites and transport of biopolymers (proteins, RNAs) is the mitochondrial outer membrane (MOM), as the MOM defines the boundary of the organelle. Recently, we have purified the MOM of T. brucei and characterized its proteome using label-free quantitative mass spectrometry for protein abundance profiling in combination with statistical analysis. Our results show that the trypanosomal MOM proteome consists of 82 proteins, two thirds of which have never been associated with mitochondria before. Among these, we identified novel factors required to regulate mitochondrial morphology and the long-elusive protein import machinery of T. brucei. A comparison with the MOM proteome of yeast defines a set of 17 common proteins that are likely present in the mitochondrial outer membrane of all eukaryotes. One of these is the Miro-GTPase Gem1. In yeast, this Ca2+-EF-Hand containing polypeptide is thought to be involved in a protein complex that physically tethers the mitochondrion to the ER. Interestingly, a putative tethering complex in mammalian cells was linked to the mitochondrial fusion/fission machinery. Thus, the concept of a protein complex-mediated connection seems to be a general and conserved feature. We are currently investigating, if such a protein complex exists in T. brucei and if the trypanosomal Gem1 protein is involved. This ER-subdomain associated with mitochondria has been termed mitochondria-associated ER-membranes or MAM. The MAM has recently been implicated to play a key role in Alzheimer’s disease. It is therefore of broad and general interest to establish other eukaryotic model systems in order to investigate the MAM-MOM connection in more detail.