Article
Refine
Year of publication
Institute
- Fachbereich Medizintechnik und Technomathematik (1593) (remove)
Document Type
- Article (1593) (remove)
Keywords
- Einspielen <Werkstoff> (7)
- FEM (4)
- Finite-Elemente-Methode (4)
- LAPS (4)
- CellDrum (3)
- Label-free detection (3)
- biosensors (3)
- hydrogen peroxide (3)
- impedance spectroscopy (3)
- shakedown analysis (3)
- Bacillus atrophaeus (2)
- Bauingenieurwesen (2)
- Boundary integral equations (2)
- CAD (2)
- Capacitive field-effect sensor (2)
- Conductive boundary condition (2)
- Einspielanalyse (2)
- Empirical process (2)
- Field-effect sensor (2)
- Goodness-of-fit test (2)
- Independence test (2)
- Light-addressable potentiometric sensor (2)
- Lipopolysaccharide (2)
- Paired sample (2)
- Parametric bootstrap (2)
- Raman spectroscopy (2)
- Shakedown analysis (2)
- Stiffness (2)
- Traglastanalyse (2)
- Transmission eigenvalues (2)
- capacitive field-effect sensors (2)
- carbonized rice husk (2)
- civil engineering (2)
- constructive alignment (2)
- damage (2)
- examination (2)
- field-effect sensor (2)
- frequency mixing magnetic detection (2)
- likelihood ratio test (2)
- limit analysis (2)
- locomotion (2)
- long-term retention (2)
- multimodal (2)
- muscle fascicle behavior (2)
- not identically distributed (2)
- practical learning (2)
- shakedown (2)
- tobacco mosaic virus (TMV) (2)
- ultrasound (2)
- ultrasound imaging (2)
- (Bio)degradation (1)
- Acceleration (1)
- Achilles tendon (1)
- Adaptive control (1)
- Afterload (1)
- Ageing (1)
- Air purification (1)
- AlterG (1)
- Alternating plasticity (1)
- Alzheimer's disease (1)
- Analysis (1)
- Analytischer Zulaessigkeitsnachweis (1)
- Anastomotic leakage (1)
- Anatomy (1)
- Annulus Fibrosus (1)
- Architectural design (1)
- Architectural gear ratio (1)
- Architektur (1)
- Arthosetherapie (1)
- Assistive technology (1)
- Asymptotic efficiency (1)
- Aufschlagversuch (1)
- Autolysis (1)
- Automatic control (1)
- Axialbelastung (1)
- Axially cracked pipe (1)
- Bacillus atrophaeus spores (1)
- Bacillus sp (1)
- Bacterial cellulose (1)
- Balance (1)
- Basis Reduktion (1)
- Basis reduction (1)
- Bicharakteristikenverfahren (1)
- Bioabsorbable (1)
- Biocomposites (1)
- Biomechanical simulation (1)
- Bioreaktor (1)
- Biosolubilization (1)
- Blutzellenlagerung (1)
- Bone quality and biomechanics (1)
- Booster Station (1)
- Bootstrap (1)
- Bootstrapping (1)
- Boundary integral equations, (1)
- Brownian Pillow (1)
- CNOT (1)
- Calorimetric gas sensor (1)
- Capacitive field-effect (1)
- Capacitive model (1)
- Carbon sources (1)
- Cardiac myocytes (1)
- Cardiac tissue (1)
- Categorial variable (1)
- Cell permeability (1)
- Cellular force (1)
- Cellulose nanostructure (1)
- Cement infiltration (1)
- Cementoblast (1)
- Censored data (1)
- Chemical images (1)
- Chemical imaging sensor (1)
- Chemical sensor (1)
- Circular Dichroism (1)
- Clusterion (1)
- Co-managed care (1)
- Coal (1)
- Collective risk model (1)
- Competitiveness (1)
- Complex System (1)
- Complex-valued eigenvalues (1)
- Compliance (1)
- Compression (1)
- Computational biomechanics (1)
- Concomitant (1)
- Conductive Boundary Condition (1)
- Conservation laws (1)
- Constitutive model (1)
- Contractile tension (1)
- Contractility (1)
- Convex optimization (1)
- Cost-effectiveness (1)
- Coverage probability (1)
- Cramér-von-Mises statistic (1)
- Cramér-von-Mises test (1)
- Cross border adjustment mechanism (1)
- Crámer–von-Mises distance (1)
- Culture media (1)
- C–V method (1)
- DNA biosensor (1)
- DNA hybridization (1)
- DPA (dipicolinic acid) (1)
- Damage mechanics theory (1)
- Decomposition (1)
- Deep Learning (1)
- Deformation (1)
- Dehydrogenase (1)
- Design-by-analysis (1)
- Diaphorase (1)
- Dimensional splitting (1)
- Disc Degeneration (1)
- Discontinuous fractures (1)
- Discrete Optimization (1)
- Distorsion des oberen Sprunggelenks (1)
- Druckbeanspruchung (1)
- Druckbehälter (1)
- Druckbelastung (1)
- Druckgeräte (1)
- Drug simulation (1)
- E-Mobility (1)
- E. coli detection (1)
- EIS capacitive sensor (1)
- ELISA (1)
- ES-FEM (1)
- Eigenvalue trajectories (1)
- Einspiel-Analyse (1)
- Einspiel-Kriterium (1)
- Einspielen (1)
- Elastizität (1)
- Elderly (1)
- Electrolyte–insulator–semiconductor (1)
- Electromagnetism (1)
- Electromechanical modeling (1)
- Elektroenzephalographie (1)
- Elemental (1)
- End-to-end colorectal anastomosis (1)
- Endothelial cells (1)
- Endothelial dysfunction (1)
- Energy-intensive industry (1)
- Enterprise information systems (1)
- Entropy solution (1)
- Environmental impact (1)
- Enzymatic biosensor (1)
- Enzyme coverage (1)
- Enzyme logic gate (1)
- Enzyme-linked immunosorbent assay (1)
- Epithel (1)
- Equivalence test (1)
- Esophageal Doppler monitor (1)
- Experiment (1)
- Exponential Euler scheme, (1)
- Exponential time differencing (1)
- External knee adduction moments (1)
- FS-FEM (1)
- Fall prevention (1)
- Fault approximation (1)
- Fault detection (1)
- Fehlerstellen (1)
- Fibroblast (1)
- Field effect (1)
- Field-effect biosensor (1)
- Finite difference methods (1)
- Finite element analysis (1)
- Finite element modelling (1)
- Fließgrenze (1)
- Floor prices (1)
- Force (1)
- Forces (1)
- Fracture configuration (1)
- Fracture simulation (1)
- Freeze–thaw process (1)
- Frequency adaption (1)
- Frequency mixing magnetic detection (1)
- Functional Delta Method (1)
- Fußball (1)
- Gamma distribution (1)
- Geriatric (1)
- German (1)
- Glaucoma (1)
- Global and local collapse (1)
- Gold nanoparticles (1)
- Gonarthrose (1)
- Goodness-of-fit tests for uniformity (1)
- Grenzwertberechnung (1)
- Ground-level falls (1)
- H2 (1)
- Hadamard differentiability (1)
- Haemodialysis (1)
- Handbike (1)
- Harnleiter (1)
- Heart tissue culture (1)
- Helmholtz equation (1)
- Hemoglobin structure (1)
- Heterostructure (1)
- Higher-order codes (1)
- Hip fractures (1)
- Hodgkin–Huxley models (1)
- Hoeffding-Blum-Kiefer-Rosenblatt independence test (1)
- Homogenization (1)
- Hotelling’s T² test (1)
- Human-Computer interaction (1)
- Hydrogen peroxide (1)
- Hydrogenotrophic methanogens (1)
- Hämoglobin (1)
- Hämoglobinstruktur (1)
- Image Reconstruction (1)
- Impedance spectroscopy (1)
- Implicit methods (1)
- Incomplete data (1)
- Induced pluripotent stem cells (1)
- Information extraction (1)
- Inotropic compounds (1)
- Integrated empirical distribution (survival) function (1)
- Interior Neumann eigenvalues (1)
- Interior transmission eigenvalues (1)
- Interior transmission problem (1)
- Intervertebral Disc (1)
- Intradiscal Pressure (1)
- Inverse Scattering (1)
- Inverse dynamic problem (1)
- Inverse kinematic problem (1)
- Inverse scattering (1)
- Inverse scattering problem (1)
- Inverse spectral problem (1)
- Ion channels (1)
- Iterative learning control (1)
- Kinetic energy (1)
- Kniegelenkarthrose (1)
- Knochen (1)
- Knochenbildung (1)
- Knochenchirugie (1)
- Knochendichte (1)
- Kohlenstofffaser (1)
- LPS (1)
- Lab-on-Chip (1)
- Langevin theory (1)
- Layer-by-layer adsorption (1)
- LbL films (1)
- Light-addressable Potentiometric Sensor (1)
- Limit analysis (1)
- Liver (1)
- Long COVID (1)
- Luftreiniger (1)
- MBST (1)
- MCDA (1)
- MOS (1)
- Machine learning (1)
- Magnetic nanoparticles (1)
- Manipulated variables (1)
- Marginal homogeneity test (1)
- Master stamp (1)
- Materialermüdung (1)
- Matrix exponential (1)
- Mechanotransduction (1)
- Medusomyces gisevi (1)
- Metascintillator (1)
- Methane (1)
- Methanogenesis (1)
- Microcirculation (1)
- Micromagnetic simulation (1)
- Mild cognitive impairment (1)
- Mobility (1)
- Mobility tests (1)
- Mobility transition (1)
- Model-driven software engineering (1)
- Monotone methods (1)
- Multi-criteria decision analysis (1)
- Multi-dimensional partial differential equations (1)
- Multi-sample problem (1)
- Multianalyte detection (1)
- Multicell (1)
- Multiple TOF kernels (1)
- Multiplexing (1)
- Muscle (1)
- Muscle Fascicle (1)
- Muscle Force (1)
- Musculoskeletal model (1)
- Musculoskeletal system (1)
- Myocardial infarction and cardiac death (1)
- NONOate (1)
- Natural fibres (1)
- Negative impedance convertor (1)
- Neural Network (1)
- Nitric Oxide (1)
- Nitric Oxide Donor (1)
- Non-parallel fissures (1)
- Nonequilibrium dynamics (1)
- Nonlinear Dynamics (1)
- Nonlinear PDEs (1)
- Nonlinear eigenvalue problems (1)
- Nucleus Pulposus (1)
- Numerical inversion of Laplace transforms (1)
- Numerical linear algebra (1)
- Numerics (1)
- O2 plasma (1)
- Ocular blood flow (1)
- Organic light-emitting diode display (1)
- Organkultur (1)
- Osteoporose (1)
- Osteoporosis (1)
- Parabolic SPDEs (1)
- Paralympic sport (1)
- Penicillin (1)
- Permeability (1)
- Permeabilität (1)
- Peroxidase (1)
- Pflanzenphysiologie (1)
- Pflanzenscanner (1)
- Pflanzenstress (1)
- Pharmacology (1)
- Photolithographic mimics (1)
- Physiology (1)
- Plant virus (1)
- Plasmacluster ion technology (1)
- Plastizität (1)
- Poly(allylamine hydrochloride) (1)
- Poly(d,l-lacticacid) (1)
- Polyimide (1)
- Polylactide acid (1)
- Polymer-matrix composites (1)
- Post-COVID-19 syndrome (1)
- Potential theory (1)
- Preference assessment (1)
- Pressure loaded crack-face (1)
- Prevention (1)
- Product-integration (1)
- Progressive plastic deformation (1)
- Prophylaxis (1)
- Proximal humerus fracture (1)
- Psychiatrische Biomarker (1)
- Pulsations (1)
- Pump System (1)
- Quartz crystal microbalance (1)
- RVA (1)
- Ratchetting (1)
- Raumluft (1)
- Reaction-diffusion systems (1)
- Real distinct pole (1)
- Real-time monitoring (1)
- Recombinant activated protein C (1)
- Red blood cell storage (1)
- Regionalization (1)
- Rehabilitation Technology and Prosthetics (1)
- Rehabilitation engineering (1)
- Resampling test (1)
- Resistive temperature detector (1)
- Resolvent Operator (1)
- Resonance-mode measurement (1)
- Retinal vessel analysis (1)
- Retinal vessels (1)
- Robotic rehabilitation (1)
- Rohr (1)
- Rohrbruch (1)
- Rotator cuff (1)
- Running (1)
- S-FEM (1)
- ScaLAPACK (1)
- Schienbeinschoner (1)
- Schlafspindeldetektion (1)
- Schwammknochen (1)
- Semi-parametric random censorship model (1)
- Septic cardiomyopathy (1)
- Shakedown (1)
- Shakedown criterion (1)
- Silk fibroin (1)
- Simulation (1)
- Simultaneous determination (1)
- Skeletal muscle (1)
- Small Aral Sea (1)
- Sn₃O₄ (1)
- Software and systems modeling (1)
- Source term (1)
- Spleen (1)
- Sprunggelenkorthesen (1)
- Stahl (1)
- Steel industry (1)
- Sterilisation process (1)
- Stress concentrations (1)
- Strukturanalyse (1)
- SunRav BookEditor (1)
- Surface imprinted polymer (1)
- Surgical Navigation and Robotics (1)
- Surgical staplers (1)
- Survival analysis (1)
- TMV adsorption (1)
- TOF PET (1)
- Ta₂O₅ gate (1)
- Technical Operations Research (TOR) (1)
- Temperaturabhängigkeit (1)
- Tendon Rupture (1)
- Tendon properties (1)
- Tendons (1)
- Tension (1)
- Tinetti test (1)
- Tissue Engineering (1)
- Tobacco mosaic virus (TMV) (1)
- Traglast (1)
- Transmission Eigenvalues (1)
- Ultrasound (1)
- Uniaxial compression test (1)
- Vapnik–Čhervonenkis class (1)
- Variable height stapler design (1)
- Vascular response (1)
- Vasomotions (1)
- Velocity (1)
- Vertebroplastie (1)
- Vertebroplasty (1)
- Viscous flow (1)
- Viskose Strömung (1)
- Viskosität (1)
- Visual field asymmetry (1)
- Volterra integral equation (1)
- Volume of confidence regions (1)
- Volume status (1)
- Wolff's Law (1)
- Wolffsches Gesetz (1)
- Wundheilung (1)
- XOR (1)
- Zeta potential (1)
- Zug-Druck Belastung (1)
- acetoin (1)
- acetoin reductase (1)
- achilles tendon (1)
- actin cytoskeleton (1)
- adipose-derived stromal cells (ASCs) (1)
- adsorption (1)
- agility (1)
- alcoholic beverages (1)
- allocation (1)
- alternierend Verformbarkeit (1)
- amperometric biosensors (1)
- anaesthetic complications (1)
- anisotropy (1)
- ankle braces (1)
- ankle sprain (1)
- annealing (1)
- aortic perfusion (1)
- aquaculture (1)
- architecture (1)
- aromatic amines (1)
- arthrosis therapy (1)
- artificial olfactory image (1)
- asymptotic relative efficiency (1)
- atomic layer deposition (1)
- barium strontium titanate (1)
- biaxial tensile experiment (1)
- bicharacteristics (1)
- bioburdens (1)
- biocompatible (1)
- biocompatible materials (1)
- biodegradabl (1)
- biodegradable electronic devices (1)
- biomechanics (1)
- biopotential electrodes (1)
- biosensor (1)
- bone density (1)
- bone structure (1)
- bootstrap (1)
- burst pressure (1)
- burst tests (1)
- calorimetric gas sensor (1)
- calorimetric gas sensor;hydrogen peroxide;wireless sensor system (1)
- cancellous bone (1)
- capacitive electrolyte–insulator–semiconductor sensors (1)
- capacitive field-effect sensor (1)
- carbon electrodes (1)
- cardiomyocyte biomechanics (1)
- catalytic metal (1)
- cell aerosolization (1)
- cell atomization (1)
- central symmetry test (1)
- cerebral small vessel disease (1)
- chance constrained programming (1)
- chemical sensor (1)
- chip-based sensor setup (1)
- cognitive impairment (1)
- community dwelling (1)
- complete block symmetry (1)
- computational fluid dynamics analysis (1)
- conditional excess distribution (1)
- conditional expectation principle (1)
- confidence interval (1)
- connective tissue (1)
- constitutive modeling (1)
- contactless conductivity sensor (1)
- correlation (1)
- coupled Néel–Brownian relaxation dynamics (1)
- covariance principle (1)
- dental trauma (1)
- dialysis (1)
- difficult airway (1)
- direct method (1)
- distance learning (1)
- distorted element (1)
- double-lumen tube intubation (1)
- drop jump (1)
- e-books (1)
- e-issues (1)
- ecological structure (1)
- eigensolvers (1)
- elastic scattering (1)
- elastic solids (1)
- electrical conductivity of liquids (1)
- electrolyte-insulator semiconductor sensor (EIS) (1)
- electromyography (1)
- electronic nose (1)
- encapsulation materials (1)
- endoluminal (1)
- endospores (1)
- energy absorption (1)
- energy dissipation (1)
- enzymatic (bio)degradation (1)
- enzymatic biosensor (1)
- enzyme cascade (1)
- epithelization (1)
- exchangeability test (1)
- extracorporeal membrane oxygenation (1)
- fatigue analyses (1)
- fibroin (1)
- fibulare Bandruptur (1)
- field-effect structure (1)
- flaw (1)
- force generation (1)
- forecast (1)
- forehead EEG (1)
- fortschreitende plastische Deformation (1)
- frequency mixing (1)
- functional data (1)
- gait (1)
- gas sensor (1)
- glucose (1)
- glucose oxidase (GOx) (1)
- gonarthrosis (1)
- goodness-of-fit test (1)
- graphene oxide (1)
- healthy aging (1)
- heavy metals (1)
- hiPS cardiomyocytes (1)
- high-intensity exercise (1)
- high-k material (1)
- horseradish peroxidase (HRP) (1)
- huge dimensional data (1)
- human dermal fibroblasts (1)
- humic acid (1)
- hydroxylation (1)
- hyper-gravity (1)
- hyperelastic (1)
- hypo-gravity (1)
- immobilization (1)
- in-ear EEG (1)
- in-situ monitoring (1)
- independence test (1)
- intraclass correlation coefficient (1)
- key performance indicators (1)
- konvexe Optimierung (1)
- lable-free detection (1)
- large language models (1)
- layer-by-layer technique (1)
- light-addressable potentiometric sensor (1)
- light-addressing technologies (1)
- lignite (1)
- limit load (1)
- lipopolysaccharide (1)
- lipopolysaccharides (1)
- load limit (1)
- magnetic actuation (1)
- magnetic beads (1)
- magnetic biosensing (1)
- magnetic nanoparticles (1)
- magnetic relaxation (1)
- magnetic sandwich immunoassay (1)
- magnetic sensing (1)
- magnetic separation (1)
- magnetic tweezers (1)
- magnetophoretic velocity (1)
- mechanical buffer (1)
- metagenomics (1)
- metal-oxide-semiconductor structure (1)
- method of fundamental solutions (1)
- microbial diversity (1)
- microfluidics (1)
- micromagnetic simulation (1)
- multi-functional material (1)
- multinomial distribution (1)
- multiparametric immunoassays (1)
- multivariate normal distribution (1)
- muscle mechanics (1)
- nanobelts (1)
- nanomaterials (1)
- nanostructured carbonized plant parts (1)
- nanostrukturierte carbonisierte Pflanzenteile (1)
- naphtols (1)
- non-simplex S-FEM elements (1)
- novel photoexcitation method (1)
- optical sensor setup (1)
- optical spore trapping (1)
- optical trapping (1)
- organosilanes (1)
- overload (1)
- pH sensors (1)
- parabolic flight (1)
- penicillin (1)
- penicillinase (1)
- performance analysis (1)
- performance testing (1)
- phenols (1)
- photoelectrochemistry (1)
- physiology (1)
- pipes (1)
- plant scanner (1)
- plant stress (1)
- plant virus detection (1)
- plug-based microfluidic device (1)
- poly(d, l-lactic acid) (1)
- polyaniline (1)
- portfolio risk (1)
- prevention (1)
- psychosocial (1)
- random effects (1)
- random effects meta-regression model (1)
- ratchetting (1)
- rehabilitation (1)
- reliability analysis (1)
- reliability of structures (1)
- retinal microvasculature (1)
- retinal vessels (1)
- running (1)
- rupture of the fibular ligament (1)
- sEMG (1)
- sarcomere operating length (1)
- scanned light pulse technique (1)
- semantic role labeling (1)
- separable Hilbert space (1)
- series elastic element behavior (1)
- shakedown analyses (1)
- shotgun sequencing (1)
- shoulder (1)
- silanization (1)
- simulation (1)
- smooth muscle contraction (1)
- softs (1)
- spatial resolution (1)
- speaker attribution (1)
- sprint start (1)
- standard error of measurement (1)
- sterilisation (1)
- sterility tests (1)
- sterilization (1)
- sterilization conditions (1)
- sterilization efficacy (1)
- sterilization methods (1)
- stiffness (1)
- stochastic programming (1)
- strain energy function (1)
- stretch reflex (1)
- stretch-shortening cycle (1)
- superparamagnetic bead (1)
- superparamagnetic nanoparticles (1)
- surface functionalization (1)
- surface modification (1)
- survival (1)
- temperature (1)
- tendon rupture (1)
- tension–torsion loading (1)
- test-retest reliability (1)
- thermal ratcheting (1)
- thermometry (1)
- tilted constant illumination (1)
- titanium dioxide photoanode (1)
- tri-lineage differentiation (1)
- turnip vein clearing virus (TVCV) (1)
- twin-fluid atomizer (1)
- ultrasonography (1)
- ultrathin gate insulators (1)
- uniformly most powerful invariant test (1)
- unloading (1)
- validation methods (1)
- vessels (1)
- videolaryngoscopy (1)
- virgin passive (1)
- viscoelasticity (1)
- visualization (1)
- walking (1)
- walking gait (1)
- wound healing (1)
- yield stress (1)
- · Psychiatrische Erkrankungen/Diagnostik (1)
High spin states in ¹⁹¹ Au
(1975)
High spin states in ¹⁹¹ Au
(1975)
Side bands in ¹⁷² Hf
(1978)
468 Scatter dose determination at the eye lens during a mask based whole brain radiotherapy (WBRT)
(2005)
The isotopes ¹³⁰,¹³²,¹³⁴,¹³⁶ Ce are investigated by means of the reactions ¹¹⁸,¹²⁰,¹²²,¹²⁴ Sn(¹⁶O, 4n) at bombarding energies between 68 and 76 MeV. From lifetime measurements a reduction of the collective behaviour is observed with increasing neutron number. Yrast cascades of rotational structure are identified up to angular momenta I=16⁺ or I=18⁺ in ¹³⁰,¹³²,¹³⁴ Ce. These cascades show a strong “back-bending” effect. In ¹³⁶ Ce no such simple yrast cascade could be found.
Band structure in ¹⁹⁰,¹⁹² Au
(1978)
Band structure in ¹⁹⁰,¹⁹² Au
(1978)
High-spin isomer in ¹³⁷ Ce
(1978)
New isomers in ¹⁴² Sm
(1980)
New isomers in ¹⁴² Sm
(1979)
New side-bands in ¹³⁴ Ce
(1981)
Side bands in ¹⁷² Hf
(1977)
Validation of a novel method for detecting and stabilizing malfunctioning areas in fuel cell stacks
(2014)
In this paper a setup for detecting malfunctioning areas of MEAs in fuel cell stacks is described. Malfunctioning areas generate electric cross currents inside bipolar plates. To exploit this we suggest bipolar plates consisting not of two but of three layers. The third one is a highly conducting layer and segmented such that the cross currents move along the segments to the surface of the stack where they can be measured by an inductive sensor. With this information a realistic model can be used to detect the malfunctioning area. Furthermore the third layer will prevent any current inhomogeneity of a malfunctioning cell to spread to neighbouring cells in the stack. In this work the results of measurements in a realistic cell setup will be compared with the results obtained in simulation studies with the same configuration. The basis for the comparison is the reliable characterisation of the electrical properties of the cell components and the implication of these results into the simulation model. The experimental studies will also show the limits in the maximum number of segments, which can be used for a reliable detection of cross currents.
α-hydroxy ketones (HK) and 1,2-diols are important building blocks for fine chemical synthesis. Here, we describe the R-selective 2,3-butanediol dehydrogenase from B. clausii DSM 8716ᵀ (BcBDH) that belongs to the metal-dependent medium chain dehydrogenases/reductases family (MDR) and catalyzes the selective asymmetric reduction of prochiral 1,2-diketones to the corresponding HK and, in some cases, the reduction of the same to the corresponding 1,2-diols. Aliphatic diketones, like 2,3-pentanedione, 2,3-hexanedione, 5-methyl-2,3-hexanedione, 3,4-hexanedione and 2,3-heptanedione are well transformed. In addition, surprisingly alkyl phenyl dicarbonyls, like 2-hydroxy-1-phenylpropan-1-one and phenylglyoxal are accepted, whereas their derivatives with two phenyl groups are not substrates. Supplementation of Mn²⁺ (1 mM) increases BcBDH's activity in biotransformations. Furthermore, the biocatalytic reduction of 5-methyl-2,3-hexanedione to mainly 5-methyl-3-hydroxy-2-hexanone with only small amounts of 5-methyl-2-hydroxy-3-hexanone within an enzyme membrane reactor is demonstrated.
The gene encoding a putative (R,R)-butane-2,3-diol dehydrogenase (bdhA) from Bacillus clausii DSM 8716T was isolated, sequenced and expressed in Escherichia coli. The amino acid sequence of the encoded protein is only distantly related to previously studied enzymes (identity 33–43%) and exhibited some uncharted peculiarities. An N-terminally StrepII-tagged enzyme variant was purified and initially characterized. The isolated enzyme catalyzed the (R)-specific oxidation of (R,R)- and meso-butane-2,3-diol to (R)- and (S)-acetoin with specific activities of 12 U/mg and 23 U/mg, respectively. Likewise, racemic acetoin was reduced with a specific activity of up to 115 U/mg yielding a mixture of (R,R)- and meso-butane-2,3-diol, while the enzyme reduced butane-2,3-dione (Vmax 74 U/mg) solely to (R,R)-butane-2,3-diol via (R)-acetoin. For these reactions only activity with the co-substrates NADH/NAD+ was observed. The enzyme accepted a selection of vicinal diketones, α-hydroxy ketones and vicinal diols as alternative substrates. Although the physiological function of the enzyme in B. clausii remains elusive, the data presented herein clearly demonstrates that the encoded enzyme is a genuine (R,R)-butane-2,3-diol dehydrogenase with potential for applications in biocatalysis and sensor development.
The enantioselective synthesis of α-hydroxy ketones and vicinal diols is an intriguing field because of the broad applicability of these molecules. Although, butandiol dehydrogenases are known to play a key role in the production of 2,3-butandiol, their potential as biocatalysts is still not well studied. Here, we investigate the biocatalytic properties of the meso-butanediol dehydrogenase from Bacillus licheniformis DSM 13T (BlBDH). The encoding gene was cloned with an N-terminal StrepII-tag and recombinantly overexpressed in E. coli. BlBDH is highly active towards several non-physiological diketones and α-hydroxyketones with varying aliphatic chain lengths or even containing phenyl moieties. By adjusting the reaction parameters in biotransformations the formation of either the α-hydroxyketone intermediate or the diol can be controlled.
A microcavity-based deoxyribonucleic acid (DNA) optical biosensor is demonstrated for the first time using synthetic sapphire for the optical cavity. Transmitted and elastic scattering intensity at 1510 nm are analyzed from a sapphire microsphere (radius 500 μm, refractive index 1.77) on an optical fiber half coupler. The 0.43 nm angular mode spacing of the resonances correlates well with the optical size of the sapphire sphere. Probe DNA consisting of a 36-mer fragment was covalently immobilized on a sapphire microsphere and hybridized with a 29-mer target DNA. Whispering gallery modes (WGMs) were monitored before the sapphire was functionalized with DNA and after it was functionalized with single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). The shift in WGMs from the surface modification with DNA was measured and correlated well with the estimated thickness of the add-on DNA layer. It is shown that ssDNA is more uniformly oriented on the sapphire surface than dsDNA. In addition, it is shown that functionalization of the sapphire spherical surface with DNA does not affect the quality factor (Q≈104) of the sapphire microspheres. The use of sapphire is especially interesting because this material is chemically resilient, biocompatible, and widely used for medical implants.
Deoxyribonucleic acid (DNA) and protein recognition are now standard tools in biology. In addition, the special optical properties of microsphere resonators expressed by the high quality factor (Q-factor) of whispering gallery modes (WGMs) or morphology dependent resonances (MDRs) have attracted the attention of the biophotonic community. Microsphere-based biosensors are considered as powerful candidates to achieve label-free recognition of single molecules due to the high sensitivity of their WGMs. When the microsphere surface is modified with biomolecules, the effective refractive index and the effective size of the microsphere change resulting in a resonant wavelength shift. The transverse electric (TE) and the transverse magnetic (TM) elastic light scattering intensity of electromagnetic waves at 600 and 1400 nm are numerically calculated for DNA and unspecific binding of proteins to the microsphere surface. The effect of changing the optical properties was studied for diamond (refractive index 2.34), glass (refractive index 1.50), and sapphire (refractive index 1.75) microspheres with a 50 µm radius. The mode spacing, the linewidth of WGMs, and the shift of resonant wavelength due to the change in radius and refractive index, were analyzed by numerical simulations. Preliminary results of unspecific binding of biomolecules are presented. The calculated shift in WGMs can be used for biomolecules detection.
In this study we show an optical biosensor concept, based on elastic light scattering from sapphire microspheres. Transmitted and elastic scattering intensity of the microspheres (radius 500 μm, refractive index 1.77) on an optical fiber half coupler is analyzed at 1510 nm. The 0.43 nm angular mode spacing of the resonances is comparable to the angular mode spacing value estimated using the optical size of the microsphere. The spectral linewidths of the resonances are in the order of 0.01 nm, which corresponds to quality factors of approximately 105. A polydopamine layer is used as a functionalizing agent on sapphire microspherical resonators in view of biosensor implementation. The varying layer thickness on the microsphere is determined as a function of the resonance wavelength shift. It is shown that polymer functionalization has a minor effect on the quality factor. This is a promising step toward the development of an optical biosensor.
In this study, we show that synthetic sapphire (Al₂O₃), an established implant material, can also serve as a platform material for biosensors comparable to nanocrystalline diamond. Sapphire chips, beads, and powder were first modified with (3-aminopropyl) triethoxysilane (APTES), followed by succinic anhydride (SA), and finally single-stranded probe DNA was EDC coupled to the functionalized layer. The presence of the APTES-SA layer on sapphire powders was confirmed by thermogravimetric analyis and Fourier-transform infrared spectroscopy. Using planar sapphire chips as substrates and X-ray photoelectron spectroscopy (XPS) as surface-sensitive tool, the sequence of individual layers was analyzed with respect to their chemical state, enabling the quantification of areal densities of the involved molecular units. Fluorescence microscopy was used to demonstrate the hybridization of fluorescently tagged target DNA to the probe DNA, including denaturation- and re-hybridization experiments. Due to its high thermal conductivity, synthetic sapphire is especially suitable as a chip material for the heat-transfer method, which was employed to distinguish complementary- and non-complementary DNA duplexes containing single-nucleotide polymorphisms. These results indicate that it is possible to detect mutations electronically with a chemically resilient and electrically insulating chip material.
Thin film chemical sensors based on chalcogenide glasses for „electronic tongue“ applications
(2001)
Development of an optimized LSO/LuYAP phoswich detector head for the Lausanne ClearPET demonstrator
(2006)
This paper describes the LSO/LuYAP phoswich detector head developed for the ClearPET small animal PET scanner demonstrator that is under construction in Lausanne within the Crystal Clear Collaboration. The detector head consists of a dual layer of 8×8 LSO and LuYAP crystal arrays coupled to a multi-anode photomultiplier tube (Hamamatsu R7600-M64). Equalistion of the LSO/LuYAP light collection is obtained through partial attenuation of the LSO scintillation light using a thin aluminum deposit of 20-35 nm on LSO and appropriate temperature regulation of the phoswich head between 30°C to 60°C. At 511keV, typical FWHM energy resolutions of the pixels of a phoswich head amounts to (28±2)% for LSO and (25±2)% for LuYAP. The LSO versus LuYAP crystal identification efficiency is better than 98%. Six detector modules have been mounted on a rotating gantry. Axial and tangential spatial resolutions were measured up to 4 cm from the scanner axis and compared to Monte Carlo simulations using GATE. FWHM spatial resolution ranges from 1.3 mm on axis to 2.6 mm at 4 cm from the axis.
An enzyme system organized in a flow device was used to mimic a reversible Controlled NOT (CNOT) gate with two input and two output signals. Reversible conversion of NAD⁺ and NADH cofactors was used to perform a XOR logic operation, while biocatalytic hydrolysis of p-nitrophenyl phosphate resulted in an Identity operation working in parallel. The first biomolecular realization of a CNOT gate is promising for integration into complex biomolecular networks and future biosensor/biomedical applications.