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51.
Michael Denker Alexa Riehle Markus Diesmann Sonja Grün 《Journal of computational neuroscience》2010,29(3):599-613
The hypothesis that cortical networks employ the coordinated activity of groups of neurons, termed assemblies, to process
information is debated. Results from multiple single-unit recordings are not conclusive because of the dramatic undersampling
of the system. However, the local field potential (LFP) is a mesoscopic signal reflecting synchronized network activity. This
raises the question whether the LFP can be employed to overcome the problem of undersampling. In a recent study in the motor
cortex of the awake behaving monkey based on the locking of coincidences to the LFP we determined a lower bound for the fraction
of spike coincidences originating from assembly activation. This quantity together with the locking of single spikes leads
to a lower bound for the fraction of spikes originating from any assembly activity. Here we derive a statistical method to
estimate the fraction of spike synchrony caused by assemblies—not its lower bound—from the spike data alone. A joint spike
and LFP surrogate data model demonstrates consistency of results and the sensitivity of the method. Combining spike and LFP
signals, we obtain an estimate of the fraction of spikes resulting from assemblies in the experimental data. 相似文献
52.
Hanno Würbel Markus Stauffacher Dietrich von Holst 《Ethology : formerly Zeitschrift fur Tierpsychologie》1996,102(3):371-385
The ontogeny of two stereotypic patterns, wire-gnawing and jumping, was studied in 24 laboratory mice: six males and six females each of two closely related outbred strains, kept under standard housing conditions, a conventional albino strain (ICR) and a nude, athymic mutant (ICR nu; hereafter: NU). All 24 individuals developed wire-gnawing after weaning at 20 d of age. In ICR one female and in NU five males and three females additionally developed jumping. ICR developed wire-gnawing between the age of 20 and 30 d, in NU jumping started at the age of 20 d, but intense jumping and wire-gnawing comparable to that of ICR did not develop in NU before the age of 40–50 d. Within each strain there was no significant difference between males and females with respect to the development of stereotypic behaviour. By contrast, ICR showed significantly more wire-gnawing but less jumping than NU. Stereotypy level increased with age up to a mean of 10.7 % of total activity in ICR and up to 7.4 % in NU at 100 d of age. However, there was huge inter- and intra-individual variability with respect to all parameters assessed in this study, i.e. total duration, number of bouts and bout length of the two stereotyped patterns. Wire-gnawing developed from outside-directed explorative climbing at the cage lid, whereas the source behaviour pattern (Mason 1991 a, Anim. Behav. 41, 1015–1037) of jumping was outside-directed explorative rearing at the cage wall. At 20 d of age, before the onset of stereotypy development, ICR showed significantly more climbing but less rearing than NU. Physical retardation of NU at weaning may account for decreased climbing ability during early ontogeny, and hence for the retarded development of wire-gnawing. The difference in early experience with either of the two patterns rather than genetic effects may be responsible for the qualitative difference between the strains with respect to the form of later stereotypy. 相似文献
53.
54.
Miles B Markus 《BMJ (Clinical research ed.)》1985,290(6481):1592
55.
56.
Luise Ehlers Karen Bannert Sarah Rohde Peggy Berlin Johannes Reiner Mats Wiese Julia Doller Markus M. Lerch Ali A. Aghdassi Fatuma Meyer Luzia Valentini Ottavia Agrifoglio Cornelia C. Metges Georg Lamprecht Robert Jaster 《Journal of cellular and molecular medicine》2020,24(15):8304-8314
Muscle wasting represents a constant pathological feature of common chronic gastrointestinal diseases, including liver cirrhosis (LC), inflammatory bowel diseases (IBD), chronic pancreatitis (CP) and pancreatic cancer (PC), and is associated with increased morbidity and mortality. Recent clinical and experimental studies point to the existence of a gut‐skeletal muscle axis that is constituted by specific gut‐derived mediators which activate pro‐ and anti‐sarcopenic signalling pathways in skeletal muscle cells. A pathophysiological link between both organs is also provided by low‐grade systemic inflammation. Animal models of LC, IBD, CP and PC represent an important resource for mechanistic and preclinical studies on disease‐associated muscle wasting. They are also required to test and validate specific anti‐sarcopenic therapies prior to clinical application. In this article, we review frequently used rodent models of muscle wasting in the context of chronic gastrointestinal diseases, survey their specific advantages and limitations and discuss possibilities for further research activities in the field. We conclude that animal models of LC‐, IBD‐ and PC‐associated sarcopenia are an essential supplement to clinical studies because they may provide additional mechanistic insights and help to identify molecular targets for therapeutic interventions in humans. 相似文献
57.
Long‐haul transportation demand is predicted to increase in the future, resulting in higher carbon dioxide emissions. Different drivetrain technologies, such as hybrid or battery electric vehicles, electrified roads, liquefied natural gas and hydrogen, might offer solutions to this problem. To assess their ecological and economic impact, these concepts were simulated including a weight and cost model to estimate the total cost of ownership. An evolutionary algorithm optimizes each vehicle to find a concept specific optimal solution. A model calculates the minimum investment in infrastructure required to meet the energy demand for each concept. A well‐to‐wheel analysis takes into account upstream and on‐road carbon dioxide emissions, to compare fully electric vehicles with conventional combustion engines. Investment in new infrastructure is the biggest drawback of electrified road concepts, although they offer low CO2 emissions. The diesel hybrid is the best compromise between carbon reduction and costs. 相似文献
58.
Forin Silvia Berger Markus Finkbeiner Matthias 《The International Journal of Life Cycle Assessment》2020,25(4):663-666
The International Journal of Life Cycle Assessment - 相似文献
59.
Stefanie J. Müller‐Schüssele Ren Wang Desire D. Gütle Jill Romer Marta Rodriguez‐Franco Martin Scholz Felix Buchert Volker M. Lüth Stanislav Kopriva Peter Drmann Markus Schwarzlnder Ralf Reski Michael Hippler Andreas J. Meyer 《The Plant journal : for cell and molecular biology》2020,103(3):1140-1154
Thiol‐based redox‐regulation is vital for coordinating chloroplast functions depending on illumination and has been throroughly investigated for thioredoxin‐dependent processes. In parallel, glutathione reductase (GR) maintains a highly reduced glutathione pool, enabling glutathione‐mediated redox buffering. Yet, how the redox cascades of the thioredoxin and glutathione redox machineries integrate metabolic regulation and detoxification of reactive oxygen species remains largely unresolved because null mutants of plastid/mitochondrial GR are embryo‐lethal in Arabidopsis thaliana. To investigate whether maintaining a highly reducing stromal glutathione redox potential (EGSH) via GR is necessary for functional photosynthesis and plant growth, we created knockout lines of the homologous enzyme in the model moss Physcomitrella patens. In these viable mutant lines, we found decreasing photosynthetic performance and plant growth with increasing light intensities, whereas ascorbate and zeaxanthin/antheraxanthin levels were elevated. By in vivo monitoring stromal EGSH dynamics, we show that stromal EGSH is highly reducing in wild‐type and clearly responsive to light, whereas an absence of GR leads to a partial glutathione oxidation, which is not rescued by light. By metabolic labelling, we reveal changing protein abundances in the GR knockout plants, pinpointing the adjustment of chloroplast proteostasis and the induction of plastid protein repair and degradation machineries. Our results indicate that the plastid thioredoxin system is not a functional backup for the plastid glutathione redox systems, whereas GR plays a critical role in maintaining efficient photosynthesis. 相似文献
60.
Bart J.M. Rooijakkers Suvi Arola Rama Velagapudi Markus B. Linder 《Biochemistry and Biophysics Reports》2020
Many cellulose degrading and modifying enzymes have distinct parts called carbohydrate binding modules (CBMs). The CBMs have been shown to increase the concentration of enzymes on the insoluble substrate and thereby enhance catalytic activity. It has been suggested that CBMs also have a role in disrupting or dispersing the insoluble cellulose substrate, but dispute remains and explicit evidence of such a mechanism is lacking. We produced the isolated CBMs from two major cellulases (Cel6A and Cel7A) from Trichoderma reesei as recombinant proteins in Escherichia coli. We then studied the viscoelastic properties of native unmodified cellulose nanofibrils (CNF) in combination with the highly purified CBMs to detect possible functional effects of the CBMs on the CNF. The two CBMs showed clearly different effects on the viscoelastic properties of CNF. The difference in effects is noteworthy, yet it was not possible to conclude for example disruptive effects. We discuss here the alternative explanations for viscoelastic effects on CNF caused by CBMs, including the effect of ionic cosolutes. 相似文献