Publications by authors named "Markus Kohler"

A reliable local-fatigue assessment approach for rotary friction-welded components does not yet exist. The scope of this paper is to present test results for the fatigue behaviour of rotary friction-welded solid shafts made of structural steel S355J2G3 (1.0570) and an approach to fatigue assessment considering residual stress.

View Article and Find Full Text PDF

Introduction: Selecting patients with lumbar degenerative spondylolisthesis (LDS) for surgery is difficult. Appropriate use criteria (AUC) have been developed to clarify the indications for LDS surgery but have not been evaluated in controlled studies.

Methods: This prospective, controlled, multicentre study involved 908 patients (561 surgical and 347 non-surgical controls; 69.

View Article and Find Full Text PDF

The current COVID-19 pandemic has aggravated pre-existing oxygen supply gaps all over the world. In fact, oxygen shortages occurred in affluent areas with highly developed healthcare systems. The state-of-affairs created much suffering and resulted in potentially preventable deaths.

View Article and Find Full Text PDF

Background: The effect of lumbar decompression on physical activity (PA) measures (measured as number of steps/day and as moderate to vigorous PA (MVPA)) is poorly understood. The aim of the current study was to compare PA in patients before and after lumbar decompression and to determine the association between change in steps/day and MVPA with change in disability, health-related quality of life (HRQOL) and pain.

Methods: Patients undergoing lumbar decompression surgery were recruited.

View Article and Find Full Text PDF

The major function of B lymphocytes is to sense antigens and to produce protective antibodies after activation. This function requires the expression of a B-cell antigen receptor (BCR), and evolutionary conserved mechanisms seem to exist that ensure that B cells without a BCR do not develop nor survive in the periphery. Here, we show that the loss of BCR expression on Burkitt lymphoma cells leads to decreased mitochondrial function and impaired metabolic flexibility.

View Article and Find Full Text PDF

Bone healing involves the interplay of immune cells, mesenchymal cells, and vasculature over the time course of regeneration. Approaches to quantify the spatiotemporal aspects of bone healing at cellular resolution during long bone healing do not yet exist. Here, a novel technique termed Limbostomy is presented, which combines intravital microendoscopy with an osteotomy.

View Article and Find Full Text PDF

Macrophages are essential players in the process of fracture healing, acting by remodeling of the extracellular matrix and enabling vascularization. Whilst activated macrophages of M1-like phenotype are present in the initial pro-inflammatory phase of hours to days of fracture healing, an anti-inflammatory M2-like macrophage phenotype is supposed to be crucial for the induction of downstream cascades of healing, especially the initiation of vascularization. In a mouse-osteotomy model, we provide a comprehensive characterization of vessel (CD31, Emcn) and macrophage phenotypes (F4/80, CD206, CD80, Mac-2) during the process of fracture healing.

View Article and Find Full Text PDF

In the past years, cellular metabolism of the immune system experienced a revival, as it has become clear that it is not merely responsible for the cellular energy supply, but also impacts on many signaling pathways and, thus, on diverse cellular functions. Label-free fluorescence lifetime imaging of the ubiquitous coenzymes NADH and NADPH (NAD(P)H-FLIM) makes it possible to monitor cellular metabolism in living cells and tissues and has already been applied to study metabolic changes both under physiologic and pathologic conditions. However, due to the complex distribution of NAD(P)H-dependent enzymes in cells, whose distribution continuously changes over time, a thorough interpretation of NAD(P)H-FLIM results, in particular, resolving the contribution of various enzymes to the overall metabolic activity, remains challenging.

View Article and Find Full Text PDF

The application of fuels from renewable sources ("alternative fuels") in aviation is important for the reduction of anthropogenic carbon dioxide emissions, but may also attribute to reduced release of particles from jet engines. The present experiment describes ground-based measurements in the framework of the ECLIF (Emission and Climate Impact of Alternative Fuels) campaign using an Airbus A320 (V2527-A5 engines) burning six fuels of chemically different composition. Two reference Jet A-1 with slightly different chemical parameters were applied and further used in combination with a Fischer-Tropsch synthetic paraffinic kerosene (FT-SPK) to prepare three semi synthetic jet fuels (SSJF) of different aromatic content.

View Article and Find Full Text PDF

This manuscript describes a high-temperature flow reactor experiment coupled to the powerful molecular beam mass spectrometry (MBMS) technique. This flexible tool offers a detailed observation of chemical gas-phase kinetics in reacting flows under well-controlled conditions. The vast range of operating conditions available in a laminar flow reactor enables access to extraordinary combustion applications that are typically not achievable by flame experiments.

View Article and Find Full Text PDF

Under oxidative stress 26S proteasomes suffer reversible disassembly into its 20S and 19S subunits, a process mediated by HSP70. This inhibits the degradation of polyubiquitinated proteins by the 26S proteasome and allows the degradation of oxidized proteins by a free 20S proteasome. Low fluxes of antimycin A-stimulated ROS production caused dimerization of mitochondrial peroxiredoxin 3 and cytosolic peroxiredoxin 2, but not peroxiredoxin overoxidation and overall oxidation of cellular protein thiols.

View Article and Find Full Text PDF

p53 is a well-known tumor suppressor that plays multiple biological roles, including the capacity to modulate metabolism at different levels. However, its metabolic role in brown adipose tissue (BAT) remains largely unknown. Herein we sought to investigate the physiological role of endogenous p53 in BAT and its implication on BAT thermogenic activity and energy balance.

View Article and Find Full Text PDF

A new high-temperature flow reactor experiment utilizing the powerful molecular beam mass spectrometry (MBMS) technique for detailed observation of gas phase kinetics in reacting flows is presented. The reactor design provides a consequent extension of the experimental portfolio of validation experiments for combustion reaction kinetics. Temperatures up to 1800 K are applicable by three individually controlled temperature zones with this atmospheric pressure flow reactor.

View Article and Find Full Text PDF

Addictive disorders are of high prevalence and often associated with other psychiatric and somatic diseases. Diagnostic procedures must be targeted to this topic and should also cover the exclusion of comorbidities, such as OCD, psychotic, mood disorders and ADHD. Severe cases, often complicated by multiple dependencies of substances and advanced stages of the disease can require the involvement of a variety of caregivers, who are requested to sufficiently cooperate and interact to guarantee an optimal outcome of treatment.

View Article and Find Full Text PDF

The combination of high-order harmonic generation (HHG) with resonant XUV excitation of a core electron into the transient valence vacancy that is created in the course of the HHG process is investigated theoretically. In this setup, the first electron performs a HHG three-step process, whereas the second electron Rabi flops between the core and the valence vacancy. The modified HHG spectrum due to recombination with the valence and the core is determined and analyzed for krypton on the 3d→4p resonance in the ion.

View Article and Find Full Text PDF

We report on a new design of a vacuum ultra violet (VUV) lamp for direct optical excitation of high laying atomic states, e.g., for excitation of metastable rare gas atoms.

View Article and Find Full Text PDF

A method is proposed for arbitrarily engineering the high-order harmonic generation phase achieved by shaping a laser pulse and employing xuv light or x rays for ionization. This renders the production of bandwidth-limited attosecond pulses possible while avoiding the use of filters for chirp compensation. By adding the first 8 Fourier components to a sinusoidal field of 1016 W/cm2, the bandwidth-limited emission of 8 as is shown to be possible from a Li2+ gas.

View Article and Find Full Text PDF

High-order harmonic generation (HHG) is investigated theoretically in the over-the-barrier ionization regime revealing the strong signature of interference between two separately ionized and separately propagating free wave packets of a single electron. The interference leads to the emission of coherent light at a photon energy corresponding to the kinetic-energy difference of the two recolliding electron quantum paths, thus complementary to the well-known classical three-step picture of HHG. As will be shown by time-frequency analysis of the emitted radiation, the process entirely dominates the coherent HHG emission after the atomic ground state has been depleted by a strong field.

View Article and Find Full Text PDF

Quantitative concentration measurements of CH and C(2) have been performed in laminar, premixed, flat flames of propene and cyclopentene with varying stoichiometry. A combination of cavity ring-down (CRD) spectroscopy and laser-induced fluorescence (LIF) was used to enable sensitive detection of these species with high spatial resolution. Previously, CH and C(2) chemistry had been studied, predominantly in methane flames, to understand potential correlations of their formation and consumption.

View Article and Find Full Text PDF

The generation of tailored femtosecond pulses with fully engineered intensity and phase profiles is demonstrated using second-harmonic generation of an Er:fiber laser in an aperiodically poled lithium niobate crystal in the undepleted pump regime. Second-harmonic pulse shapes, including Gaussian, stepped, square, and multiple pulses have been characterized using cross-correlation frequency-resolved optical gating and have been shown to agree well with theory.

View Article and Find Full Text PDF

Objective: Oxidative stress and inflammatory processes accelerate the formation of advanced glycation end products (AGE), e.g. of pentosidine.

View Article and Find Full Text PDF

Serum markers, e.show $132#g., the protein S-100B and neuron-specific enolase (NSE), are recognized to give additional information about the extension and prognosis of brain damage.

View Article and Find Full Text PDF