The Role of Gut Microbiota in an Ischemic Stroke

The intestinal microbiome, the largest reservoir of microorganisms in the human body, plays an important role in neurological development and aging as well as in brain disorders such as an ischemic stroke. Increasing knowledge about mediators and triggered pathways has contributed to a better understanding of the interaction between the gut-brain axis and the brain-gut axis. Intestinal bacteria produce neuroactive compounds and can modulate neuronal function, which affects behavior after an ischemic stroke. In addition, intestinal microorganisms affect host metabolism and immune status, which in turn affects the neuronal network in the ischemic brain. Here we discuss the latest results of animal and human research on two-way communication along the gut-brain axis in an ischemic stroke. Moreover, several reports have revealed the impact of an ischemic stroke on gut dysfunction and intestinal dysbiosis, highlighting the delicate play between the brain, intestines and microbiome after this acute brain injury. Despite our growing knowledge of intestinal microflora in shaping brain health, host metabolism, the immune system and disease progression, its therapeutic options in an ischemic stroke have not yet been fully utilized. This review shows the role of the gut microflora-brain axis in an ischemic stroke and assesses the potential role of intestinal microflora in the onset, progression and recovery post-stroke.     

Book Reviews

Books reviewed in this article:
Recent Developments in Spatial Analysis. Spatial Statistics, Behavioural Modelling, and Computational Intelligence. (Advances in Spatial Science) Manfred M. Fischer and Arthur Getis
Regional and Local Potential for Transformation in Poland. G. Gorzelak
The City and its Sciences. C.S. Bertuglia, G. Bianchi, A. Mela (Eds.)     

Combined measurements – A way to improve the measurement accuracy of an additive quantity

We show a way to take measurements of an additive quantity on several objects that gives the possibility to get considerably better accuracy of results than that one can get when the measurements are performed on particular objects one by one, when the same instrument is used in both cases. The theory of such measurements is described and the possible gain in accuracy derived. When n = 4–6 objects are to be measured, the uncertainty of combined measurement can be lowered by better than 2–4 times, respectively. Theoretical predictions were found to agree with both real and computer simulated measurements.     

The Effect of New Flame Retardant Systems Containing Montmorillonite-Butyl Acrylate Nanoclay on the Flammability Properties of Polyuerethane Polymer

The montmorillonite (MMT) was modified by butyl acrylate polymer. The newly modified MMT was characterized by TGA and DSC techniques. The modified MMT constitute melamine phosphate and different carbonizing agents and new flame retardant systems for poly urethane (PU) polymer. The flammability properties of the different PU formulations were characterized by cone calorimeter and ISO 1210 tests.The new flame retardant system gave the poly urethane polymer higher fire class, V0 (PU3 & 23). The thermal stability of the PU formulations was also improved.     

DMA Study of the Molecular Structure of Porcine Fat in-Water Emulsions Stabilised by Potato Starch

The aim of the study was to determine how the molecular structure of porcine fat-in-water type emulsions stabilised with potato starch affected their rheomechanical properties. Dynamic mechanical analysis (DMA) and instrumental analysis of the texture were the method used in experiments. Starch gels with concentrations corresponding to the water starch concentration of the examined emulsions were used as control systems. The analysis of the starch and starch–fat systems showed that the values characterising their rheomechanical and textural properties reflected the spatial reaction of the amylose matrix to dynamic mechanical interactions. Changes in their values resulted from conformational changes in the structure of segments and nodes of the lattice, conditioned by the concentration of starch and the presence of fat. As a result of these changes, starch–fat emulsions are distinguished by greater densities of network segments and nearly two times greater functionalities of nodes than starch gels. The instrumental analysis of the texture showed that the values of the texture parameters in the starch gels were greater than in the starch–fat emulsions. The high values of the correlation coefficients (R~0.9) between the texture determinants and the rheological parameters proved that there was a strong correlation between the textural properties of the tested systems and their rheomechanical properties.     

Assessing the applicability of groundwater monitoring data in the modelling of soil water retention characteristics

The present work focuses on an assessment of the applicability of groundwater table (GWT) measures in the modelling of soil water retention characteristics (SWRC) using artificial neural network (ANN) methods. Model development, testing, validation and verification were performed using data collected across two decades from soil profiles at full‐scale research objects located in Southwest Poland. A positive effect was observed between the initial GWT position data and the accuracy of soil water reserve estimation. On the other hand, no significant effects were observed following the implementation of GWT fluctuation data over the entire growing season. The ANN tests that used data of either soil water content or GWT position gave analogous results. This revealed that the easily obtained data (temperature, precipitation and GWT position) are the most accurate modelling parameters. These outcomes can be used to simplify modelling input data/parameters/variables in the practical implementation of the proposed SWRC modelling variants.     

Determination of the interfacial area and mass transfer coefficients in the Taylor gas–liquid flow in a microchannel

The interfacial area in the Taylor (slug) gas–liquid flow in a microchannel was measured by the Danckwerts' (chemical) method, using CO₂ absorption from the CO₂/N₂ mixture into KHCO₃/K₂CO₃ buffer solutions, containing NaOCl as a catalyst. The rate of absorption was determined and the Danckwerts' plots were constructed. Reasonable agreement with the geometrical area measured photographically was obtained. This fact allowed to determine for the first time the mass transfer coefficients separately for liquid film and liquid caps. A correlation for the calculation of mass transfer coefficients has been proposed.     

Crystal and electronic structure of PbTe/CdTe nanostructures

In this article, the authors reported a theoretical study of structural and electronic properties of PbTe inclusions in CdTe matrix as well as CdTe nano-clusters in PbTe matrix. The structural properties are studied by ab initio methods. A tight-binding model is constructed to calculate the electron density of states (DOS) of the systems. In contrast to the ab initio methods, the latter allows studying nanostructures with diameters comparable to the real ones. The calculations show that both kinds of inclusions lead to changes of the DOS of the carriers near the Fermi level, which may affect optical, electrical and thermoelectric properties of the material. These changes depend on the size, shape, and concentration of inclusions.     

Stabilization of butter with deodorized rosemary extract

 The antioxidative activity of the ethanolic extract of deodorized rosemary (Rosmarinus officinalis L.) in butter was tested. The extract was added at two concentrations, 0.05 and 0.1%, to the cream before churning. The samples of isolated fat were stored at 60°C for 38 days and their peroxide values (PVs) determined periodically. The relative changes in the proton absorption patterns of the butter lipids during storage were monitored by nuclear magnetic resonance (NMR) spectroscopy. The samples treated with 0.05 and 0.1% extract had much longer induction periods than the control. A significant correlation (r = 0.980) was measured between the ratio of aliphatic to olefinic protons (R _ao) and the PVs of the butter fat. The deodorized ethanolic extract was also subjected to TLC separation on silica gel plates and UV spectral analysis. The UV spectrum of the extract had maxima at 286 and 328 nm. Six spots attributed to phenolic compounds were observed on the TLC plate. The extract also exhibited strong antioxidant activity in a β-carotene-linoleate model system. Received: 11 July 1997