555 research outputs found
Social Work Perceptions of Job Satisfaction in Host and Primary Settings: A Comparative Analysis
Job satisfaction can have personal and professional effects on social workers as well as the quality of service provided to clients. Structural variables such as supervision or role ambiguity may effect job satisfaction, but the intensity to which it effects the social worker may be different from setting to setting. The purpose of this research is to demonstrate the contribution of selected factors associated with job satisfaction in two different settings. The research design for this exploratory study, is a cross-sectional mailed survey. A random sample of 75 social workers in host settings and primary settings were sent surveys. A comparative analysis of the data was completed utilizing non-parametric statistics. The majority of social workers in both settings were satisfied with their job, however, specific factors were found to effect job satisfaction differently in host and primary settings
The effect of Fermi surface curvature on low-energy properties of fermions with singular interactions
We discuss the effect of Fermi surface curvature on long-distance/time
asymptotic behaviors of two-dimensional fermions interacting via a gapless mode
described by an effective gauge field-like propagator. By comparing the
predictions based on the idea of multi-dimensional bosonization with those of
the strong- coupling Eliashberg approach, we demonstrate that an agreement
between the two requires a further extension of the former technique.Comment: Latex, 4+ pages. Phys. Rev. Lett., to appea
Monitoring the Petermann Ice Island with TanDEM-X
This paper presents the processing of TanDEM-X acquisitions for the monitoring of the topography of the Petermann ice island. In this particular case the area under study is continuously moving and the acquisition geometry is changing, so the processing of the iceberg’s DEMs is challenging and additional effects are to be considered. The SAR processing chain used is presented and the results obtained summarized, showing the effects and limitations observed during the process
Hybrid Amperometric and Potentiometric Sensing Based on a CMOS ISFET Array
Potentiometry and amperometry are some of the most important techniques for electroanalytical applications. Integrating these two techniques on a single chip using CMOS technology paves the way for more analysis and measurement of chemical solutions. In this paper, we describe the integration of electrode transducers (amperometry) on an ion imager based on an ISFET array (potentiometry). In particular, this integration enables the spatial representation of the potential distribution of active electrodes in a chemical solution under investigation
A 16 x 16 CMOS amperometric microelectrode array for simultaneous electrochemical measurements
There is a requirement for an electrochemical sensor technology capable of making multivariate measurements in environmental, healthcare, and manufacturing applications. Here, we present a new device that is highly parallelized with an excellent bandwidth. For the first time, electrochemical cross-talk for a chip-based sensor is defined and characterized. The new CMOS electrochemical sensor chip is capable of simultaneously taking multiple, independent electroanalytical measurements. The chip is structured as an electrochemical cell microarray, comprised of a microelectrode array connected to embedded self-contained potentiostats. Speed and sensitivity are essential in dynamic variable electrochemical systems. Owing to the parallel function of the system, rapid data collection is possible while maintaining an appropriately low-scan rate. By performing multiple, simultaneous cyclic voltammetry scans in each of the electrochemical cells on the chip surface, we are able to show (with a cell-to-cell pitch of 456 μm) that the signal cross-talk is only 12% between nearest neighbors in a ferrocene rich solution. The system opens up the possibility to use multiple independently controlled electrochemical sensors on a single chip for applications in DNA sensing, medical diagnostics, environmental sensing, the food industry, neuronal sensing, and drug discovery
Composite SUVR: a new method for boosting Alzheimer's disease monitoring and diagnostic performance, applied to tau PET
Background: Abnormal brain tau protein accumulation is strongly linked to multiple neurodegenerative disorders. Currently, brain tau pathology is quantified in vivo using tau PET by calculating the Standardized Uptake Value Ratio (SUVR) of target and reference regions of interest (ROIs).
Recent work (Schwarz et al., 2021) in Alzheimer’s Disease (AD) explored various target and reference ROIs to report performance of SUVR as a biomarker for diagnosis, disease monitoring, and clinical trial efficacy/eligibility (sample size estimate, SSE). Here we introduce a new method and biomarker: Composite SUVR (CUVR). /
Methods: We analyzed longitudinal SUV data from ADNI in the available 103 participants having three or more tau PET scans ([18F]AV-1451): 58 cognitively normal (CN); 21 mild cognitive impairment; 24 probable AD. In the spirit of SUVR and statistical ROIs (Chen, et al., NeuroImage 2010), we calculate CUVR as the SUV ratio of two composite regions. Our novel method is that the composite regions are determined by a genetic algorithm that searches the possible 3^96 combinations of regions from FreeSurfer’s default atlas. We compare performance of SUVR with CUVR.
Performance metrics follow Schwarz et al.: a linear mixed-effects model quantifies longitudinal group separation by tau accumulation rate (t statistic between fixed effects for CN and AD) and longitudinal precision (model residuals’ standard deviation). CUVR and SUVR values were log-transformed before model fitting.
We calculated SSE for a hypothetical clinical trial designed for 80% power to reduce tau PET accumulation by 20% (vs. placebo) in non-CN individuals. /
Results: Our method identified a CUVR biomarker involving 60 regions. Figure-1 shows the vast performance improvement of CUVR versus the best-performing SUVR (inferior-temporal target; eroded subcortical white matter reference). Group separation improved by 2.9x (t = 9.57 vs 3.32); longitudinal precision by 6.5x (residual std = 0.331% vs 2.14%); and CUVR required a smaller sample size by 3.9x (83 vs 318). /
Conclusions: Our simple data-driven approach discovered a new tau PET biomarker called CUVR. Experimental results show state-of-the-art longitudinal group separation, longitudinal precision, and clinical trial enrichment. The remarkable performance improvements provide compelling evidence for using CUVR for both eligibility and efficacy in Alzheimer’s disease clinical trials, particularly of anti-tau therapies
Untersuchung von Veränderungen cerebraler Metaboliten bei depressiven Patienten im Laufe einer EKT-Serie mittels 1 H-Magnetresonanzspektroskopie
14 Patienten mit Indikation zur Elektrokrampftherapie (EKT) bei einer schweren depressiven Episode wurden vor EKT, nach 6 EKT und am Ende der EKT-Serie untersucht. Mittels Magnetresonanzspektroskopie wurde N-Acetyl-Aspartat, Cholin, Creatin, Glutamin/Glutamat (Glx) und myo-Inositol in Hippocampus und linkem Cingulum gemessen. Erfolgreiche EKT führt im Cingulum zu einem Anstieg von Cholin, erklärbar durch vermehrten Membranumsatz. Die Zunahme von Creatin im Hippocampus zeigt einen Zusammenhang zwischen Stimmung und Energieversorgung. Der gemessene Glx-Anstieg könnte mitverantwortlich für die Gedächtnisstörung nach EKT sein. Die vorliegende Arbeit zeigt, dass im Hippocampus und Cingulum metabolische Veränderungen unter EKT auftreten, die sowohl klinische Effizienz als auch Nebenwirkungen erklären können. Weitere Untersuchungen von Cholin, Creatin und Glx an großen Patientenzahlen können zum tieferen Verständnis der depressiven Störungen sowie der Wirkungsweise der EKT beitragen
Ligating Catalytically Active Peptides onto Microporous Polymers: A General Route Toward Specifically-Functional High Surface Area Platforms
A versatile post-synthetic modification strategy to functionalize a high surface area microporous network (MPN-OH) by bio-orthogonal inverse electron-demand Diels-Alder (IEDDA) ligation is presented. While the polymer matrix is modified with a readily accessible norbornene isocyanate (Nor-NCO), a series of functional units presenting the robust asymmetric 1,2,4,5-tetrazine (Tz) allows easy functionalization of the MPN by chemoselective Nor/Tz ligation. A generic route is demonstrated, modulating the internal interfaces by introducing carboxylates, amides or amino acids as well as an oligopeptide d-Pro-Pro-Glu organocatalyst. The MPN-Pz-Peptide construct largely retains the catalytic activity and selectivity in an enantioselective enamine catalysis, demonstrates remarkable availability in different solvents, offers heterogeneous organocatalysis in bulk and shows stability in recycling settings.Peer Reviewe
An experimental approach for investigating many-body phenomena in Rydberg-interacting quantum systems
Recent developments in the study of ultracold Rydberg gases demand an
advanced level of experimental sophistication, in which high atomic and optical
densities must be combined with excellent control of external fields and
sensitive Rydberg atom detection. We describe a tailored experimental system
used to produce and study Rydberg-interacting atoms excited from dense
ultracold atomic gases. The experiment has been optimized for fast duty cycles
using a high flux cold atom source and a three beam optical dipole trap. The
latter enables tuning of the atomic density and temperature over several orders
of magnitude, all the way to the Bose-Einstein condensation transition. An
electrode structure surrounding the atoms allows for precise control over
electric fields and single-particle sensitive field ionization detection of
Rydberg atoms. We review two experiments which highlight the influence of
strong Rydberg--Rydberg interactions on different many-body systems. First, the
Rydberg blockade effect is used to pre-structure an atomic gas prior to its
spontaneous evolution into an ultracold plasma. Second, hybrid states of
photons and atoms called dark-state polaritons are studied. By looking at the
statistical distribution of Rydberg excited atoms we reveal correlations
between dark-state polaritons. These experiments will ultimately provide a
deeper understanding of many-body phenomena in strongly-interacting regimes,
including the study of strongly-coupled plasmas and interfaces between atoms
and light at the quantum level.Comment: 14 pages, 11 figures; submitted to a special issue of 'Frontiers of
Physics' dedicated to 'Quantum Foundation and Technology: Frontiers and
Future
Peptide‐based Organocatalyst on Stage: Functionalizing Mesoporous Silica by Tetrazine‐Norbornene Ligation
Organocatalysis via the enamine mechanism developed to one of the most relevant tools in carbonyl chemistry and is widely used in asymmetric organic synthesis. In this work, a strategy is presented to conveniently immobilize a peptide-based catalyst on silica supports for use in continuous flow catalysis reactions. A set of different porous silica supports is investigated spanning from mesoporous silica particles with defined pore sizes suitable for packed bed column reactors to silica monoliths with hierarchical meso-macropore spaces. While the silica supports are functionalized with norbornene entities, the peptide-based organocatalyst is modified with a tetrazine moiety, enabling the immobilization via inverse electron-demand Diels-Alder (IEDDA) reaction. The ligation results in catalyst loadings up to 0.2 mmol g-1, without compromising the mesopore network. The catalytic activity of the materials is proven by the asymmetric C−C coupling reaction of n-butanal to ß-nitrostyrene proceeding in high yield and enantioselectivity in both batch and continuous flow setups.Peer Reviewe
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