3,801 research outputs found
Ultrasonic emission method enables testing of adhesive bonds
Detection of acoustic energy emitted by adhesive bonds subjected to tensile stresses at frequencies above sixteen kilocycles per second is used as a method for determining bond strength. This method is used in measuring adhesive bond strengths on metal honeycomb core panels
Dot patterns provide reproducible flaw areas for study of adhesive bonds
Photographic production of a small-dot pattern of known geometry on the surface of a substrate for controlled area degradation enables a study of adhesive bond strengths. These dot patterns may also be applied to force-limiting devices which must depend on the adhesive bonding strength between mating surfaces
Nondestructive testing for evaluation of strength of bonded material
Nondestructive testing of adhesive bond strengt
Synapse Dysfunctions in Multiple Sclerosis
Multiple sclerosis (MS) is a chronic neuroinflammatory disease of the central nervous system (CNS) affecting nearly three million humans worldwide. In MS, cells of an auto-reactive immune
system invade the brain and cause neuroinflammation. Neuroinflammation triggers a complex,
multi-faceted harmful process not only in the white matter but also in the grey matter of the brain.
In the grey matter, neuroinflammation causes synapse dysfunctions. Synapse dysfunctions in MS
occur early and independent from white matter demyelination and are likely correlates of cognitive
and mental symptoms in MS. Disturbed synapse/glia interactions and elevated neuroinflammatory
signals play a central role. Glutamatergic excitotoxic synapse damage emerges as a major mechanism.
We review synapse/glia communication under normal conditions and summarize how this communication becomes malfunctional during neuroinflammation in MS. We discuss mechanisms of how
disturbed glia/synapse communication can lead to synapse dysfunctions, signaling dysbalance, and
neurodegeneration in MS
On the local metric property in multivariate extremes
Many multivariate data sets exhibit a form of positive dependence, which can
either appear globally between all variables or only locally within particular
subgroups. A popular notion of positive dependence that allows for localized
positivity is positive association. In this work we introduce the notion of
extremal positive association for multivariate extremes from threshold
exceedances. Via a sufficient condition for extremal association, we show that
extremal association generalizes extremal tree models. For H\"usler--Reiss
distributions the sufficient condition permits a parametric description that we
call the metric property. As the parameter of a H\"usler--Reiss distribution is
a Euclidean distance matrix, the metric property relates to research in
electrical network theory and Euclidean geometry. We show that the metric
property can be localized with respect to a graph and study surrogate
likelihood inference. This gives rise to a two-step estimation procedure for
locally metrical H\"usler--Reiss graphical models. The second step allows for a
simple dual problem, which is implemented via a gradient descent algorithm.
Finally, we demonstrate our results on simulated and real data.Comment: 22 pages, 4 figure
Kosmischer Staub im Nano-Labor : ein Blick in die Kinderstube des Sonnensystems
Staubwolken sind im Universum die Geburtsstätten neuer Sterne. Dort wiederholen sich Prozesse, die vor 4,56 Milliarden Jahren auch zur Entstehung unseres Sonnensystems geführt haben. Noch heute gibt es Zeugen aus dieser Zeit: Kometenstaub, Sternenstaub und interstellarer Staub. Die »Stardust-Mission« hat sie eingefangen, und Frankfurter Geowissenschaftler haben darin – dank modernster Labor-Analytik – erstaunliche Funde gemacht
The alternative Medicago truncatula defense proteome of ROS - defective transgenic roots during early microbial infection
ROP-type GTPases of plants function as molecular switches within elementary signal transduction pathways such as the regulation of ROS synthesis via activation of NADPH oxidases (RBOH-respiratory burst oxidase homolog in plants). Previously, we reported that silencing of the Medicago truncatula GTPase MtROP9 led to reduced ROS production and suppressed induction of ROS-related enzymes in transgenic roots (MtROP9i) infected with pathogenic (Aphanomyces euteiches) and symbiotic microorganisms (Glomus intraradices, Sinorhizobium meliloti). While fungal infections were enhanced, S. meliloti infection was drastically impaired. In this study, we investigate the temporal proteome response of M. truncatula MtROP9i transgenic roots during the same microbial interactions under conditions of deprived potential to synthesize ROS. In comparison with control roots (Mtvector), we present a comprehensive proteomic analysis using sensitive MS protein identification. For four early infection time-points (1, 3, 5, 24 hpi), 733 spots were found to be different in abundance: 213 spots comprising 984 proteins (607 unique) were identified after S. meliloti infection, 230 spots comprising 796 proteins (580 unique) after G. intraradices infection, and 290 spots comprising 1240 proteins (828 unique) after A. euteiches infection. Data evaluation by GelMap in combination with a heatmap tool allowed recognition of key proteome changes during microbial interactions under conditions of hampered ROS synthesis. Overall, the number of induced proteins in MtROP9i was low as compared with controls, indicating a dual function of ROS in defense signaling as well as alternative response patterns activated during microbial infection. Qualitative analysis of induced proteins showed that enzymes linked to ROS production and scavenging were highly induced in control roots, while in MtROP9i the majority of proteins were involved in alternative defense pathways such as cell wall and protein degradation
Rabconnectin-3α/DMXL2 Is Locally Enriched at the Synaptic Ribbon of Rod Photoreceptor Synapses
Ribbon synapses reliably transmit synaptic signals over a broad signalling range. Rod
photoreceptor ribbon synapses are capable of transmitting signals generated by the absorption of
single photons. The high precision of ribbon synapses emphasizes the need for particularly efficient
signalling mechanisms. Synaptic ribbons are presynaptic specializations of ribbon synapses and are
anchored to the active zone. Synaptic ribbons bind many synaptic vesicles that are delivered to the
active zone for continuous and faithful signalling. In the present study we demonstrate with independent antibodies at the light- and electron microscopic level that rabconnectin-3α (RC3α)—alternative
name Dmx-like 2 (DMXL2)—is localized to the synaptic ribbons of rod photoreceptor synapses in
the mouse retina. In the brain, RC3α-containing complexes are known to interact with important
components of synaptic vesicles, including Rab3-activating/inactivating enzymes, priming proteins
and the vesicular H+
-ATPase that acidifies the synaptic vesicle lumen to promote full neurotransmitter loading. The association of RC3α/DMXL2 with rod synaptic ribbons of the mouse retina could
enable these structures to deliver only fully signalling-competent synaptic vesicles to the active zone
thus contributing to reliable synaptic communication
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