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In JoVE (1)
Other Publications (16)
- Circulation
- Applied Optics
- Würzburger Medizinhistorische Mitteilungen / Im Auftrage Der Würzburger Medizinhistorischen Gesellschaft Und in Verbindung Mit Dem Institut Für Geschichte Der Medizin Der Universität Würzburg
- European Journal of Pharmacology
- The Journal of Rheumatology
- Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
- Magnetic Resonance in Medicine : Official Journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine
- Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
- Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
- Ecology Letters
- Magnetic Resonance in Medicine : Official Journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine
- Physical Chemistry Chemical Physics : PCCP
- Proceedings of the National Academy of Sciences of the United States of America
- Science (New York, N.Y.)
- European Journal of Cardio-thoracic Surgery : Official Journal of the European Association for Cardio-thoracic Surgery
- Applied and Environmental Microbiology
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Articles by Johannes Schneider in JoVE
JoVE Immunology and Infection
Encelliga Analys av Bacillus subtilis Biofilmer Använda fluorescensmikroskopi och flödescytometri
Institute for Molecular Infection Biology (IMIB), University of Würzburg
Mikrobiella biofilmer i allmänhet utgörs av distinkta subpopulationer av specialiserade celler. Enkel-cell-analys av dessa underpopulationer kräver användning av fluorescerande reportrar. Här beskriver vi ett protokoll för att visualisera och övervaka flera subpopulationswithin
Other articles by Johannes Schneider on PubMed
Midterm Results After Stentless Mitral Valve Replacement
To analyze the midterm clinical results after stentless mitral valve (SMV) replacement.
Aerosol Lidar Intercomparison in the Framework of the EARLINET Project. 2. Aerosol Backscatter Algorithms
An intercomparison of aerosol backscatter lidar algorithms was performed in 2001 within the framework of the European Aerosol Research Lidar Network to Establish an Aerosol Climatology (EARLINET). The objective of this research was to test the correctness of the algorithms and the influence of the lidar ratio used by the various lidar teams involved in the EARLINET for calculation of backscatter-coefficient profiles from the lidar signals. The exercise consisted of processing synthetic lidar signals of various degrees of difficulty. One of these profiles contained height-dependent lidar ratios to test the vertical influence of those profiles on the various retrieval algorithms. Furthermore, a realistic incomplete overlap of laser beam and receiver field of view was introduced to remind the teams to take great care in the nearest range to the lidar. The intercomparison was performed in three stages with increasing knowledge on the input parameters. First, only the lidar signals were distributed; this is the most realistic stage. Afterward the lidar ratio profiles and the reference values at calibration height were provided. The unknown height-dependent lidar ratio had the largest influence on the retrieval, whereas the unknown reference value was of minor importance. These results show the necessity of making additional independent measurements, which can provide us with a suitable approximation of the lidar ratio. The final stage proves in general, that the data evaluation schemes of the different groups of lidar systems work well.
[The History of Massage in the Ways of Life and Healing in India]
The use of massage in India can be accounted for back to the time of the first indo-aryan settlements; its is however, likely that massage was already in use during the preceding era of the Indus valley culture.The important cultural function of the ancient practice of home massage can be seen in that massage was often linked to social, religious or ritual customs. Massage was considered to be beneficial to health. The classic Ayurveda texts mention massage in this sense and recommend it as an almost indispensible healing factor. To this day, massage is regularly used in India for the promotion of general health and fitness as well as in treating minor health problems. Ayurvedic doctors also employ massage as a complete therapy to be applied systematically in the treatment of serious illness. Massage is most commonly applied to the entire body or individual body parts with the aid of ample amounts of warmed oils and, at times, other substances which are specific to the patient's constitution. The usual massage method is similar in some ways to the western method. The Ayurveda system, moreover, has a wide range of special massage methods which are used to treat particular illnesses. While today the efficacy and effect of western massage is, in large part, accounted for scientifically, in India, common, traditional massage is usually employed based on ancient experience. The general social conditions in southern Asia will likely ensure that these types of massage will continue to be a respected and frequently practised aspect of Indian culture in the future.
Differential Effects of Human Ether-a-go-go-related Gene (HERG) Blocking Agents on QT Duration Variability in Conscious Dogs
The effects of drugs that inhibit human ether-a-go-go-related gene (HERG) related cardiac potassium channels on the variability of QT duration as a sign of repolarisation instability were evaluated in conscious telemetered dogs. QT duration variability was determined using a beat-to-beat analysis before and after the infusions of HERG channel blocking agents. Variability was evaluated as increased mean width (P(width)) and length (P(length)) of Poincaré plots of 100 consecutive beats. As HERG channel blockers which are associated with arrhythmias of the torsades de pointes (TdP) type, dofetilide and sotalol were infused. Verapamil was used as an HERG channel blocker that is not associated with TdP. Dofetilide (0.01 and 0.03 mg/kg) dose-dependently prolonged QT(c) duration (12% and 16%). Dofetilide also induced an increase of QT variability that reached statistical significance for P(length) at the higher dose (64%). A dose of 3 mg/kg sotalol neither prolonged QT(c) duration nor QT duration variability. In contrast, at 10 mg/kg sotalol prolonged QT(c) duration (15%) and increased P(length) (33%). Doses of 0.1 and 0.3 mg/kg verapamil did not increase QT(c) duration nor QT time variability. QT duration variability in conscious dogs may be a useful preclinical marker to discriminate pro-arrhythmogenic and non-arrhythmogenic activities of HERG blocking agents.
Human Endogenous Retrovirus HERV-K(HML-2) Rec Expression and Transcriptional Activities in Normal and Rheumatoid Arthritis Synovia
Despite abundance in the genome, the possible functions of human endogenous retrovirus (HERV) sequences are not well understood. The involvement of HERV in various disease conditions, such as germ cell tumors or autoimmune diseases like rheumatoid arthritis (RA), has been suggested. We investigated expression of HERV-K(HML-2) env-derived transcripts in normal and RA synovia.
Statistical Analysis of Financial Returns for a Multiagent Order Book Model of Asset Trading
We recently introduced a realistic order book model [T. Preis, Europhys. Lett. 75, 510 (2006)] which is able to generate the stylized facts of financial markets. We analyze this model in detail, explain the consequences of the use of different groups of traders, and focus on the foundation of a nontrivial Hurst exponent based on the introduction of a market trend. Our order book model supports the theoretical argument that a nontrivial Hurst exponent implies not necessarily long-term correlations. A coupling of the order placement depth to the market trend can produce fat tails, which can be described by a truncated Lévy distribution.
BOLD Imaging in the Mouse Brain Using a TurboCRAZED Sequence at High Magnetic Fields
Functional MRI (fMRI) based on the detection of intermolecular double-quantum coherences (iDQC) has previously been shown to provide pronounced activation signal. For fMRI in small animals at very high magnetic fields, the essential fast gradient echo-based readout methods become problematic. Here, rapid intermolecular double-quantum coherence (iDQC) imaging was implemented, combining the iDQC preparation sequence with a Turbo spin echo-like readout. Four-step phase cycling and a novel intensity-ordered k-space encoding scheme with separate acquisition of odd and even echoes were essential to optimize signal to noise ratio efficiency. Compared with a single echo readout of iDQC signal, acceleration of factor 16 was achieved in phantoms using the novel method at 17.6 Tesla. In vivo, echo trains consisting of 32 echoes were possible and images of the mouse brain were obtained in 30 s. The blood oxygen level dependent (BOLD) effect in the mouse brain upon change of breathing gas was observed as average signal change of (6.3 +/- 1.1)% in iDQC images. Signal changes in conventional multi spin echo images were (4.4 +/- 2.3)% and (8.3 +/- 3.8)% with gradient echo methods. Combination of T(2)*-weighting with the fast iDQC sequence may yield higher signal changes than with either method alone, and establish fast iDQC imaging a robust tool for high field fMRI in small animals.
Packing a Multidisperse System of Hard Disks in a Circular Environment
We consider the problem of finding the densest closed packing of hard disks with proposed different radii in a circular environment, such that the radius of the circumcircle is minimal. With our approach, we are able to find denser packings for various problem instances than known from the literature. Both for the dynamics of the simulation and for the optimum values of the radii of the circumcircles, we find various scaling laws.
Ultrametricity Property of Energy Landscapes of Multidisperse Packing Problems
We consider the problem of finding the densest closed packing of hard disks with proposed different radii in a circular environment, such that the radius of the circumcircle is minimal. The subspace of the quasioptimum configurations of this problem exhibits the property of ultrametricity.
Reduction of Rare Soil Microbes Modifies Plant-herbivore Interactions
Rare species are assumed to have little impact on community interactions and ecosystem processes. However, very few studies have actually attempted to quantify the role of rare species in ecosystems. Here we compare effects of soil community assemblages on plant-herbivore interactions and show that reduction of rare soil microbes increases both plant biomass and plant nutritional quality. Two crop plant species growing in soil where rare microbes were reduced, had tissues of higher nutritional quality, which theoretically makes them more susceptible to pest organisms such as shoot-feeding aphids and root-feeding nematodes. Reduction of rare microbes increased aphid body size in the absence of nematodes; nematodes always reduced aphid body size independent of the soil microbial community. This study is the first to show that rare soil microbes are not redundant but may play a role in crop protection by enhancing aboveground and belowground plant defence. It remains to be tested whether these are direct effects of rare soil microbes on plants and herbivores, or indirect effects via shifts in the microbial soil community assemblages.
Robust Spatially Selective Excitation Using Radiofrequency Pulses Adapted to the Effective Spatially Encoding Magnetic Fields
Multidimensional spatially selective excitation (SSE) has stimulated a variety of useful applications in magnetic resonance imaging and magnetic resonance spectroscopy, which have regained considerable interest after the recent introduction of parallel excitation. For SSE, radiofrequency pulses are designed specifically for certain time-courses of spatially encoding magnetic fields (SEM) which are applied simultaneously with the radiofrequency pulses. However, experimental imperfections of gradient-systems and undesired SEM field contributions often prevent the correct co-action of radiofrequency pulses and gradient-waveforms and therefore degrade the fidelity of excitation patterns, especially for parallel excitation. To cope with such imperfections, a classical measurement of k-space-trajectories can be performed followed by an adaptation of the SSE-pulses. However, this method is limited to linear SEM field distributions, which are describable in the k-space-formalism. Hence, this work presents a more sophisticated method consisting in a spatially resolved measurement of the temporal phase evolution of the transverse magnetization. This exhaustive phase information can be incorporated into pulse-design algorithms to compensate even for undesired spatially nonlinear, dynamic SEM field contributions. Both approaches are assessed in various experimental scenarios and individual benefits and limitations are discussed. The adaptation of SSE-pulses to experimentally achieved calibration data turned out to be very beneficial, and especially the novel spatially resolved method exhibited high potential for robust SSE even in adverse experimental setups.
Efficient and Robust Strong-field Control of Population Transfer in Sensitizer Dyes with Designed Femtosecond Laser Pulses
We demonstrate control of electronic population transfer in molecules with the help of appropriately shaped femtosecond laser pulses. To this end we investigate two photosensitizer dyes in solution being prepared in the triplet ground state. Excitation within the triplet system is followed by intersystem crossing and the corresponding singlet fluorescence is monitored as a measure of population transfer in the triplet system. We record control landscapes with respect to the fluorescence intensity on both dyes by a systematic variation of laser pulse shapes combining second order and third order dispersion. In the strong-field regime we find highly structured topologies with large areas of maximum or minimum population transfer being insensitive over a certain range of applied laser intensities thus demonstrating robustness. We then compare our experimental results with simulations on generic molecular potentials by solving the time-dependent Schrödinger equation for excitation with shaped pulses. Control landscapes with respect to population transfer confirm the general trends from experiments. An analysis of regions with maximum or minimum population transfer indicates that coherent processes are responsible for the outcome of our excitation process. The physical mechanisms of joint motion of ground and excited state wave packets or population of a vibrational eigenstate in the excited state permit us to discuss the molecular dynamics in an atom-like picture.
Switching Processes in Financial Markets
For an intriguing variety of switching processes in nature, the underlying complex system abruptly changes from one state to another in a highly discontinuous fashion. Financial market fluctuations are characterized by many abrupt switchings creating upward trends and downward trends, on time scales ranging from macroscopic trends persisting for hundreds of days to microscopic trends persisting for a few minutes. The question arises whether these ubiquitous switching processes have quantifiable features independent of the time horizon studied. We find striking scale-free behavior of the transaction volume after each switching. Our findings can be interpreted as being consistent with time-dependent collective behavior of financial market participants. We test the possible universality of our result by performing a parallel analysis of fluctuations in time intervals between transactions. We suggest that the well known catastrophic bubbles that occur on large time scales--such as the most recent financial crisis--may not be outliers but single dramatic representatives caused by the formation of increasing and decreasing trends on time scales varying over nine orders of magnitude from very large down to very small.
Deciphering the Rhizosphere Microbiome for Disease-suppressive Bacteria
Disease-suppressive soils are exceptional ecosystems in which crop plants suffer less from specific soil-borne pathogens than expected owing to the activities of other soil microorganisms. For most disease-suppressive soils, the microbes and mechanisms involved in pathogen control are unknown. By coupling PhyloChip-based metagenomics of the rhizosphere microbiome with culture-dependent functional analyses, we identified key bacterial taxa and genes involved in suppression of a fungal root pathogen. More than 33,000 bacterial and archaeal species were detected, with Proteobacteria, Firmicutes, and Actinobacteria consistently associated with disease suppression. Members of the γ-Proteobacteria were shown to have disease-suppressive activity governed by nonribosomal peptide synthetases. Our data indicate that upon attack by a fungal root pathogen, plants can exploit microbial consortia from soil for protection against infections.
Mid-term Results of Endoscopic Mitral Valve Repair in Combination with Endocardial or Epicardial Ablation
Concomitant ablative therapy for atrial fibrillation can be effective at converting patients to normal sinus rhythm and at maintaining a regular rhythm for at least 5 years. We provide herein a comparison of an endocardial approach using Cryoablation with an epicardial approach using a suction-based RF ablation technology.
Streptomycin-induced Expression in Bacillus Subtilis of YtnP, a Lactonase-homologous Protein That Inhibits Development and Streptomycin Production in Streptomyces Griseus
Bacillus subtilis induces expression of the gene ytnP in the presence of the antimicrobial streptomycin, produced by the Gram-positive bacterium Streptomyces griseus. ytnP encodes a lactonase-homologous protein that is able to inhibit the signaling pathway required for the streptomycin production and development of aerial mycelium in S. griseus.
