461 research outputs found
The hospital organization of the future
The future of hospital Nuclear Medicine is triggered by the hospital
organisation itself. In general, the hospital organisation of
the present requires substantial changes in order to be competitive,
economical, and abreast of the rapid progresses in
medical developments and patient management. It also must
be flexible to changes in health politics. In this special report an
organisational hospital structure is outlined which may help
encounter the challenging hospital future. Some hospitals have
already implemented convincing changes, whereas others are
far behind
Conceptualization of an Anthropomorphic Replacement Hand with a Sensory Feedback System
In this paper, a concept for an anthropomorphic replacement hand cast with silicone with an integrated sensory feedback system is presented. In order to construct the personalized replacement hand, a 3D scan of a healthy hand was used to create a 3D-printed mold using computer-aided design (CAD). To allow for movement of the index and middle fingers, a motorized orthosis was used. Information about the applied force for grasping and the degree of flexion of the fingers is registered using two pressure sensors and one bending sensor in each movable finger. To integrate the sensors and additional cavities for increased flexibility, the fingers were cast in three parts, separately from the rest of the hand. A silicone adhesive (Silpuran 4200) was examined to combine the individual parts afterwards. For this, tests with different geometries were carried out. Furthermore, different test series for the secure integration of the sensors were performed, including measurements of the registered information of the sensors. Based on these findings, skin-toned individual fingers and a replacement hand with integrated sensors were created. Using Silpuran 4200, it was possible to integrate the needed cavities and to place the sensors securely into the hand while retaining full flexion using a motorized orthosis. The measurements during different loadings and while grasping various objects proved that it is possible to realize such a sensory feedback system in a replacement hand. As a result, it can be stated that the cost-effective realization of a personalized, anthropomorphic replacement hand with an integrated sensory feedback system is possible using 3D scanning and 3D printing. By integrating smaller sensors, the risk of damaging the sensors through movement could be decreased
Nuclear imaging and semi-invasive electrocardiography in CRT
Cardiac resynchronisation therapy (CRT) is a promising treatment option in patients with chronic heart failure. In this article the roles of semi-invasive esophageal left-heart electrocardiography and functional cardiac nuclear imaging in the field of CRT are highlighted, as the combination of both could be a favourable diagnostic approach in special cardiac situations. Also original esophageal left heart electrogram data of exemplary CRT patients is presented
Colloquium: Atomic spin chains on surfaces
In the present Colloquium, we focus on the properties of 1-D magnetic systems
on solid surfaces. From the emulation of 1-D quantum phases to the potential
realization of Majorana edge states, spin chains are unique systems to study.
The advent of scanning tunnelling microscope (STM) based techniques has
permitted us to engineer spin chains in an atom-by-atom fashion via atom
manipulation and to access their spin states on the ultimate atomic scale.
Here, we present the current state of research on spin correlations and
dynamics of atomic spin chains as studied by the STM. After a brief review of
the main properties of spin chains on solid surfaces, we classify spin chains
according to the coupling of their magnetic moments with the holding substrate.
This classification scheme takes into account that the nature and lifetimes of
the spin-chain excitation intrinsically depend on the holding substrate. We
first show the interest of using insulating layers on metals, which generally
results in an increase in the spin state's lifetimes such that their quantized
nature gets evident and they are individually accessible. Next, we show that
the use of semiconductor substrates promises additional control through the
tunable electron density via doping. When the coupling to the substrate is
increased for spin chains on metals, the substrate conduction electron mediated
interactions can lead to emergent exotic phases of the coupled spin
chain-substrate conduction electron system. A particularly interesting example
is furnished by superconductors. Magnetic impurities induce states in the
superconducting gap. Due to the extended nature of the spin chain, the in-gap
states develop into bands that can lead to the emergence of 1-D topological
superconductivity and, consequently to the appearance of Majorana edge states
A microfluidic perspective on conventional in vitro transcranial direct current stimulation methods
Transcranial direct current stimulation (tDCS) is a promising non-invasive brain stimulation method to treat neurological and psychiatric diseases. However, its underlying neural mechanisms warrant further investigation. Indeed, dose–response interrelations are poorly understood. Placing explanted brain tissue, mostly from mice or rats, into a uniform direct current electric field (dcEF) is a well-established in vitro system to elucidate the neural mechanism of tDCS. Nevertheless, we will show that generating a defined, uniform, and constant dcEF throughout a brain slice is challenging. This article critically reviews the methods used to generate and calibrate a uniform dcEF. We use finite element analysis (FEA) to evaluate the widely used parallel electrode configuration and show that it may not reliably generate uniform dcEF within a brain slice inside an open interface or submerged chamber. Moreover, equivalent circuit analysis and measurements inside a testing chamber suggest that calibrating the dcEF intensity with two recording electrodes can inaccurately capture the true EF magnitude in the targeted tissue when specific criteria are not met. Finally, we outline why microfluidic chambers are an effective and calibration-free approach of generating spatiotemporally uniform dcEF for DCS in vitro studies, facilitating accurate and fine-scale dcEF adjustments. We are convinced that improving the precision and addressing the limitations of current experimental platforms will substantially improve the reproducibility of in vitro experimental results. A better mechanistic understanding of dose–response relations will ultimately facilitate more effective non-invasive stimulation therapies in patients
Genetische Variabilität im dystrobrevin-binding protein 1 (DTNBP1)-Gen : Bedeutung für den Entstehungsprozess schizophrener Störungen
Obwohl das Krankheitsbild der Schizophrenie schon lange bekannt ist, sind die Ursachen, Risikofaktoren und Pathogenese der Erkrankung noch weitestgehend unbekannt. Dieses ist jedoch von zentraler Bedeutung, da die zumeist chronisch verlaufenden schizophrenen Störungen weitreichende psychosoziale Konsequenzen für Betroffene und ihr Umfeld haben. Als bisher größter Risikofaktor konnte die genetische bzw. familiäre Belastung identifiziert werden. So wird angenommen, dass der Anteil genetischer Faktoren am Entstehungsprozess der Erkrankung bei 82 bis 84% liegt. Durch zahlreiche genomweite Kopplungsuntersuchungen konnten bereits mehrere chromosomale Regionen identifiziert werden, in denen Krankheitsgene für die schizophrene Störung vermutet werden. Bei einer der Kopplungsregionen handelt es sich Chromosom 6p21-24, in ihr führten systematische Untersuchungen auf ein Kopplungsungleichgewicht (LD) zur Identifikation des putativen Krankheitsgens dysbindin-binding-protein-1 (DTNBP1). Dass es sich hierbei tatsächlich um ein Dispositionsgen für schizophrene Störungen handelt, ist durch die positiven Assoziationsergebnisse anzunehmen, die an 11 unabhängigen Kollektiven mit schizophrener Störung unterschiedlicher Ethnizität erhobenen wurden. Zum Zeitpunkt unserer Untersuchungen lagen noch keine unabhängigen Assoziationsbefunde mit genetischen Varianten am DTNBP1-Locus und schizophrenen Störungen vor. Im Rahmen einer Replikationsanalyse untersuchten wir 5 SNP-Marker, die bei der initialen Studie die deutlichsten Assoziationsbefunde gezeigt hatten. Insgesamt wurden 3 unabhängige Fall-Kontroll-Kollektive aus Polen (174 Patienten mit schizophrener Störung, 120 Kontrollen), aus Schweden (88 Patienten, 54 Kontrollen) und aus Deutschland (199 Patienten, 219 Kontrollen) untersucht. In der Einzelmarkeranalyse fanden sich nur im schwedischen Kollektiv für einen Marker signifikante Assoziationshinweise. In diesem Kollektiv waren darüber hinaus zahlreiche Haplotypen zum Erkrankungsstatus assoziiert. Da die positiven Ergebnisse anderer Arbeitsgruppen an Kollektiven mit hoher Krankheitsdichte erhoben wurden, führten wir eine Zusatzanalyse durch, in der wir unsere Kollektive nach Vorliegen einer positiven Familienanamnese stratifizierten. Trotz erheblicher Verringerung der Fallzahlen in den Kollektiven erhielten wir in der Einzelmarkeranalyse im schwedischen Kollektiv für zwei weitere Marker positive Assoziationshinweise. Ebenso verstärkten sich die Befunde der Haplotypanalyse im schwedischen Kollektiv. Dass sich bei den Statifikationsanalysen keine positiven Befunde in dem deutschen und dem polnischen Kollektiv ergaben, muss auf den Verlust an statistischer Aussagekraft (Power) zurückgeführt werden, der sich durch die Verringerung der Fallzahlen in diesen Stichproben ergab. Aufgrund unserer Befunde und der Ergebnisse anderer Arbeitsgruppen ist davon auszugehen, dass das DTNBP1 ein Dispositionsgen für schizophrene Störungen ist. Unsere Untersuchung deutet zudem darauf hin, dass der Effekt des DTNBP1-Gens bei Vorliegen einer positiven Familiarität am stärksten ist. Allerdings konnten die krankheitsverursachenden Varianten innerhalb des DTNBP1-Locus bislang nicht identifiziert werden. Die bisherigen Daten deuten darauf hin, dass es sich um populationsspezifische genetische Veränderungen handelt, da unterschiedliche Allele- und Haplotypen in den untersuchten Populationen krankheitsassoziiert waren. Zudem wird es sich bei den krankheitsdisponierenden Veränderungen um Varianten handeln, die die Genexpression oder Genregulation betreffen. Trotz umfangreicher Resequenzierungen der kodierenden DTNBP1-Genabschnitte in unterschiedlichen Patientenkollektiven konnte bislang keine funktionelle Variante identifiziert werden. Zudem liegen Ergebnisse zur allelspezifischen DTNBP1-Expression vor, wonach das risikoassoziierte Transkript eine signifikant verminderte Expression zeigte. Zusammenfassend gibt die Identifikation des Krankheitsgens DTNBP1 bei schizophrenen Störungen Anlass zur Hoffnung, dass hierdurch zukünftig weitere genetische und nicht-genetische Risikomarker detektiert werden können (Gen-Gen- und Gen-Umwelt-Interaktionen). Durch detaillierte Genotyp-Phänotyp-Analysen wird ggf. auch eine mehr biologisch begründete Diagnostik schizophrener Störungen möglich werden. Zudem könnten zellbiologische Untersuchungen dazu führen, dass Pharmazeutika entwickelt werden, die eine effektivere und gezieltere Behandlung schizophrener Störungen ermöglichen. Somit könnte mit der Identifikation vom DTNBP1 als Dispositionsfaktor für schizophrene Störungen das Auftreten und der Verlauf dieser Erkrankung positiv beeinflusst werden. Die Ergebnisse vorliegender Arbeit können hierzu einen Beitrag leisten
High diversity of Bacidia (Ramalinaceae, Lecanorales) species in the Caucasus as revealed by molecular and morphological analyses
During a study of the incompletely known lichen flora of the Caucasus, we analyzed 237 specimens of corticolous Bacidia s. str. collected in the Northern and Southern Caucasus, including Armenia, Azerbaijan, Georgia, and Russia. Of these, 54 specimens belonging to 11 species of Bacidia s. str. were selected for molecular studies, representing the observed morphological variability of the genus. We obtained 142 sequences from three RNA-coding genes (nrITS, nrLSU, and mtSSU) and two protein-coding genes (RPB1 and RPB2). The single and concatenated datasets were complemented with Bacidia s. str. sequences from GenBank and subjected to Bayesian inference and two maximum likelihood analyses (RAxML and IQ-TREE). The resulting trees yielded highly concordant topologies of the groups and corresponded with previous results, supporting two main clades correlating with apothecia pigmentation. Our analyses are the first to reveal the presence of Bacidia heterochroa in the Caucasus. An exceptionally high degree of morphological plasticity was found in the Rubella and Suffusa groups. As a result of morphological examination and phylogenetic results, B. caucasica (Suffusa group) was described as new to science. Furthermore, two putative taxa in the Rubella group, Bacidia inconspicua ined. and B. maritima ined., were introduced. This study furthers our understanding and documentation of the understudied lichen flora of the Caucasus, bringing the total number of Bacidia species for the region to 13
Kinetics of Martensite Decomposition and Microstructure Stability of Ti-6246 during Rapid Heating to Service Temperatures
The aerospace alloy Ti-6246 was subjected to inductive heat treatments with high heating and quenching rates (up to 1500 K/s) while being applied to an in situ diffraction study at the HEMS beamline P07B at DESY. Thereby, the characterization of the emerging phases was possible at any point in the process. The heat treatment schedules include the preparation of Ti-6246 samples by means of a homogenization treatment and subsequent quenching to trigger α″-martensite formation. In order to simulate fast reheating within the scope of application, the samples were reheated to the upper range of possible service temperatures (550–650 °C) with a heating rate of 100 K/s. In a second heat treatment design, the homogenized and quenched sample state was exposed to high-temperature tempering at 840 °C, which aims for the elimination of α″. Again, fast reheating to the same service temperatures was executed. With the aim of this approach, the stability of the microstructure consisting of α-Ti, β-Ti and α″-martensite was characterized. Further, the martensite decomposition path was analyzed. It shows a two-tier nature, firstly approaching the bcc β-unit cell in the low-temperature range (<400 °C) but subsequently transforming into an hcp-like unit cell and later on into equilibrium α-Ti
SterÂilÂizÂaÂtion imÂpacts on marÂine sedÂiÂment - Are we able to inÂacÂtivÂate miÂcroorÂganÂisms in enÂvirÂonÂmental samples?
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