Neuroprotective effect from stem bark extracts of Knema laurina against H2O2- and Aβ1–42-induced cell death in human SH-SY5Y cells

The stem bark extracts of Knema laurina inhibited the hydrogen peroxide (H₂O₂)- and aggregated amyloid β-peptide 1–42 length (Aβ_1–42)-induced cell death in differentiated SH-SY5Y cells. Exposure of 250 μM H₂O₂ or 20 μM Aβ_1–42 to the cells for 24 h reduced 50% of cell viability. Pretreatment of cells with ethyl acetate extract (EAE) or n-butanol extract (BE) at 300 μg/mL and then exposure to H₂O₂ protected the cells against the neurotoxic effects of H₂O₂. Besides, methanolic extract (ME) at 1 and 10 μg/mL exerted neuroprotective effect on Aβ_1–42-induced toxicity to the cells. These results showed that EAE, BE and ME exhibited neuroprotective activities against H₂O₂- and Aβ_1–42-induced cell death. Flavonoids (3–6) and β-sitosterol glucoside (8) were isolated from the EAE. Compound 1 was isolated from hexane extract, and compounds 2 and 7 were isolated from dichloromethane extract. All these observations provide the possible evidence for contribution in the neuroprotective effects.     

Evaluating Feasibility of Human Tissue Engineered Respiratory Epithelium Construct as a Potential Model for Tracheal Mucosal Reconstruction

The normal function of the airway epithelium is vital for the host’s well-being. Conditions that might compromise the structure and functionality of the airway epithelium include congenital tracheal anomalies, infection, trauma and post-intubation injuries. Recently, the onset of COVID-19 and its complications in managing respiratory failure further intensified the need for tracheal tissue replacement. Thus far, plenty of naturally derived, synthetic or allogeneic materials have been studied for their applicability in tracheal tissue replacement. However, a reliable tracheal replacement material is missing. Therefore, this study used a tissue engineering approach for constructing tracheal tissue. Human respiratory epithelial cells (RECs) were isolated from nasal turbinate, and the cells were incorporated into a calcium chloride-polymerized human blood plasma to form a human tissue respiratory epithelial construct (HTREC). The quality of HTREC in vitro, focusing on the cellular proliferation, differentiation and distribution of the RECs, was examined using histological, gene expression and immunocytochemical analysis. Histological analysis showed a homogenous distribution of RECs within the HTREC, with increased proliferation of the residing RECs within 4 days of investigation. Gene expression analysis revealed a significant increase (p < 0.05) in gene expression level of proliferative and respiratory epithelial-specific markers Ki67 and MUC5B, respectively, within 4 days of investigation. Immunohistochemical analysis also confirmed the expression of Ki67 and MUC5AC markers in residing RECs within the HTREC. The findings show that calcium chloride-polymerized human blood plasma is a suitable material, which supports viability, proliferation and mucin secreting phenotype of RECs, and this suggests that HTREC can be a potential candidate for respiratory epithelial tissue reconstruction.     

Addition of polysaccharides influences colloidal interactions during latex film formation along with film morphology and permeability

In this paper, the effect of two polysaccharides (chitosan and dextran) on latex film morphology and porosity is investigated with atomic force microscopy, and the water permeability of the films is examined as well. Furthermore, latex films formed with mixtures of dextran and poly(ethylene glycol), PEG, are investigated. The results show that latex films without added polymers have the most homogeneous and dense morphology. In films containing dextran the highest degree of flocculation is observed, while these films do not show the highest water permeability. The highest permeability is observed in films containing chitosan and film porosity and permeability correlate positively to increasing chitosan concentration. The permeability of the latex films containing dextran and PEG accelerates with time. Since addition of these polymers to latex suspensions give rise to different morphologies and film permeabilities, this approach has promising abilities for control of film properties and, thus, has potential within controlled drug release.     

Supraleitung in Seltenerdmetall-Carbidhalogeniden des Typs SE2X2C2

Superconductivity in Rare Earth Metal Carbide Halides of the Type SE₂X₂C₂ The metallic nature of the carbide halides Y₂X₂C₂ is due to Y? C covalency. The superconductivity of the compounds is attributed to a pairwise attraction of conduction electrons by C₂-π* states at the Fermi level. The hypothesis is followed by experiments and band structure calculations. – Neutron powder diffraction reveals d(C? C) = 128(1) pm for Y₂Br₂C₂. X-ray single crystal investigations on Y₂Br₂C₂ and Y₂I_1.5Br_0.5C₂ show a characteristic variation of the coordination of the C₂ unit. Systematic changes of the average halide radius in Y₂(X,X′)₂C₂ (X,X′ = Br, Cl I, Cl and I, Br) lead to a monotonic increase of T_c = 2.3 K (X = Cl) via T_c = 5.05 K (X = Br) to a maximum T_c = 11.2 K for Y₂I_1.6Br_0.4C₂. No isotope effect for ¹²C/¹³C could be detected. Photoelectron spectra of Y₂Br₂C₂ (excitation energies between 40 and 140 eV) are compared with the results of band structure calculations (LMTO, E.H.). The electronic structure reveals two bands crossing the Fermi level. One of them has C₂-π*-Y-d_xz,yz character and exhibits a saddle-point at E_F. The other intersects the Fermi level with large dispersion and has exclusively Y-d character at the crossing point. The results are discussed with respect to theoretical models (van Hove singularity, local pairs and itinerant electrons).     

New explicit group iterative methods in the solution of two dimensional hyperbolic equations

In this paper, we present the development of new explicit group relaxation methods which solve the two dimensional second order hyperbolic telegraph equation subject to specific initial and Dirichlet boundary conditions. The explicit group methods use small fixed group formulations derived from a combination of the rotated five-point finite difference approximation together with the centered five-point centered difference approximation on different grid spacings. The resulting schemes involve three levels finite difference approximations with second order accuracies. Analyses are presented to confirm the unconditional stability of the difference schemes. Numerical experimentations are also conducted to compare the new methods with some existing schemes.     

Polytypie und Phasenbreite der Yttriumcarbidbromide 1T- und 3R—Y2Br2C1–x

The Polytypism and Phase Width of the Yttrium Carbide Bromides 1T? Y₂Br₂C_1–x and 3R? Y₂Br₂C_1–x Y₂Br₂C crystallizes in two modifications, 1T? Y₂Br₂C and 3 R? Y₂Br₂C. These are temperature polytypes, and 1 T? Y₂Br₂C is the high temperature form. The transition temperature is 1 400 K. Both modifications show a range of homogeneity with Y₂Br₂C_1–x (0.0 ≤ x ≤ 0.3). For decreasing carbon content the c-lattice parameter increases, the colour of the compound changes from brown-black to bright-silver and the electrical conductivity changes from semiconducting to metallic behaviour. Extended Hueckel calculations indicate metallic conductivity for x > 0 to arise from the occupation of Y? Y metal bonding states above the gap.     

Magnetic superlattices with variable interlayer exchange coupling: a new approach for the investigation of low-dimensional magnetism

We have investigated the magnetic order in an [Fe(2)/(VHx)(13)] x 200 superlattice as a function of temperature and hydrogen content in the vanadium layers. A J(radially)-T magnetic phase diagram was established where J(radially) denotes the interlayer exchange coupling between adjacent Fe planes. We propose that Fe/V superlattices, in which the ratio of interlayer to intralayer coupling can be tuned continuously and reversibly via hydrogen in the nonmagnetic vanadium, offer a new approach for the study of low-dimensional magnetism and crossover effects near the transition from ferromagnetic to antiferromagnetic order.     

Höhensteuerung eines Tagesspeicherkraftwerks

Zusammenfassung Der während eines bestimmten Zeitraumes, etwa einem Tag, anliegende Zufluß soll optimal in Energie umgesetzt werden, m.a.W. die Energieausbeute pro Tag soll maximiert werden. Es wird ein Tagesspeicherkraftwerk betrachtet, bei dem die Kapazität des Zuflußstollens von der jeweiligen Speicherhöhe abhängt.Das grundsätzliche Verhalten des Systems wird zunächst an einem Modell mit linearen Kennlinien und an Hand von idealisierten Zuflußsituationen studiert. Anschließend wird ein Modell, worin reale Kennlinien und Zuflußsituationen stückweise linear approximiert werden, formuliert und numerisch gelöst.

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Summary A given influx during a certain time interval, say a day, is to be transformed into energy in an optimal way. In other words the production of energy per day is to be maximized. We discuss a small hydro energy storage plant (one day's reservoir capacity) where the capacity of the influx tunnel depends on the actual head of the reservoir.First we analyse the system with the help of a simplified model with both linear tunnel capacity and linear reservoir volume function and piecewise constant influx. Then reality is modelled with piecewise linear approximation and the system is solved numerically.

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Die Arbeit wurde im Rahmen des Projekts Nr. 3472 vom Fonds zur Förderung der österreichischen Forschung unterstützt. Dem Fonds sei an dieser Stelle herzlich gedankt.