Structure-activity relationship studies on the immune stimulatory effects of base-modified CpG toll-like receptor 9 agonists

Synthetic oligodeoxynucleotides containing unmethylated deoxycytidylyl-deoxyguanosine dinucleotide (CpG) motifs are able to stimulate potent immune responses through a signaling pathway involving Toll-like receptor 9 (TLR9). We have investigated the structure-activity relationship (SAR) of base-modified CpG oligonucleotides with TLR9 by measuring TLR9 activation by 20-mer oligonucleotides having just a single human recognition motif (5'-GTCGTT-3') in functional cell-based TLR9 assays. Substitution of guanine by hypoxanthine and 6-thioguanine resulted in activity similar to the unmodified parent molecule, whereas purine, 2-aminopurine, 2,6-diaminopurine, and 8-oxo-7,8-dihydroguanine substitution resulted in approximately 40-60 % reduction in activity, and 7-deazaguanine substitution led to the strongest (80 %) reduction in TLR9 stimulation. Furthermore, none of the investigated modifications at C5 and N4 of cytosine were well tolerated with respect to human TLR9 stimulation. Our results are compatible with a SAR model in which guanine is recognized by the Hoogsteen site, and C5 is most critical for recognition of cytosine. In addition, we found significant species-specific differences between human and murine TLR9 recognition, which demonstrates the importance of choosing appropriate assay systems for SAR studies.     

Effect of gadolinium ions on the structure and magnetic properties of zinc-borate glasses and glass ceramics

X-ray diffraction (XRD), electron paramagnetic resonance (EPR), and magnetic susceptibility measurements have been employed to investigate the samples from the (Gd₂O₃) _x ·(B₂O₃)_(60−x)·(ZnO)₄₀ (0 ≤ x ≤ 20 mol%) system. The XRD pattern for the prepared samples shows that the vitreous phase is present only for x ≤ 15 mol%. For the samples containing 20 mol% Gd₂O₃ the presence of a unique crystalline phase, GdBO₃, embedded in a vitreous matrix was evidenced. In this case the XRD patterns show the presence of nanometer sized crystals (64 nm) in a glassy matrix. The EPR spectra of the studied samples exhibit three important features with effective g-values of ≈6, 2.8, 2.0 and a weaker feature at g ≈ 4.8. For low Gd₂O₃ contents (x < 3 mol%), the EPR spectra have the typical ‘‘U’’-type shape. For higher contents of Gd₂O₃ (x ≥ 3 mol%), the spectral features are broadened and finally are dominated by a single broad absorption line located at g ≈ 2.0. This broad EPR line is associated to the Gd³⁺ ions present predominantly as clustered species. Magnetic susceptibility data show that for x > 1 mol% the Gd³⁺ ions are present not only as isolated species but also as species coupled through antiferromagnetic exchange interactions.     

CuInS2-Poly(3-(ethyl-4-butanoate)thiophene) nanocomposite solar cells: Preparation by an in situ formation route, performance and stability issues

In this contribution we present an in situ method for the preparation of CuInS₂-poly(3-(ethyl-4-butanoate)thiophene) (P3EBT) nanocomposite layers and their application in nanocomposite solar cells. A precursor solution containing copper and indium salts, thiourea and the conjugated polymer was prepared in pyridine, which was coated onto glass/ITO substrates followed by a heating step at 180 °C. The heating step induced the formation of the CuInS₂ nanoparticles homogeneously dispersed in the conjugated polymer matrix. The formation of the nanocomposite was investigated in situ by X-ray scattering techniques and TEM methods showing that nano-scaled CuInS₂ was formed. By addition of small amounts of zinc salt to the precursor solution, zinc containing CuInS₂ (ZCIS) was formed. ZCIS-P3EBT active layers exhibited higher V_OC than CuInS₂-P3EBT layers and showed efficiencies of about 0.4%. Additionally the stability of the solar cells was tested over a time scale of 172 h.     

Tip of the tongue selectivity and motor learning in the palatal area

This study assessed the ability of the tongue tip to accurately select intraoral targets embedded in an upper palatal tongue-computer interface, using 18 able-bodied volunteers. Four performance measures, based on modifications to Fitts's Law, were determined for three different tongue-computer interface layouts. The layouts differed with respect to number and location of the targets in the palatal interface. Assessment of intraoral target selection speed and accuracy revealed that performance was indeed dependent on the location and distance between the targets. Performances were faster and more accurate for targets located farther away from the base of the tongue in comparison to posterior and medial targets. A regression model was built, which predicted intraoral target selection time based on target location and movement amplitude better than the predicted by using a standard Fitts's Law model. A 30% improvement in the speed and accuracy over three daily practice sessions of 30 min emphasizes the remarkable motor learning abilities of the tongue musculature and provides further evidence that the tongue is useful for operating computer-interface technologies.     

New super-orthogonal space-time trellis codes using differential M-PSK for noncoherent mobile communication systems with two transmit antennas

In this paper, we develop super-orthogonal space-time trellis codes (SOSTTCs) using differential binary phase-shift keying, quadriphase-shift keying and eight-phase shift keying for noncoherent communication systems with two transmit antennas without channel state information at the receiver. Based on a differential encoding scheme proposed by Tarokh and Jafarkhani, we propose a new decoding algorithm with reduced decoding complexity. To evaluate the performance of the SOSTTCs by way of computer simulations, a geometric two-ring channel model is employed throughout. The simulation results show that the new decoding algorithm has the same decoding performance compared with the traditional decoding strategy, while it reduces significantly the overall computing complexity. As expected the system performance depends greatly on the antenna spacing and on the angular spread of the incoming waves. For fair comparison, we also design SOSTTCs for coherent detection of the same complexity as those demonstrated for the noncoherent case. As in the case of classical single antenna transmission systems, the coherent scheme outperforms the differential one by approximately 3 dB for SOSTTCs as well.     

Note on the effect of thermal radiation in the linearized Rosseland approximation on the heat transfer characteristics of various boundary layer flows

In the latter years the title problem has been examined in a large number of research papers. The present Note emphasizes, however, that the effect of thermal radiation in the linearized Rosseland approximation is quite trivial, both physically and computationally. Namely, it always reduces to a simple rescaling of the Prandtl number by a factor involving the radiation parameter. This implies that a comprehensive study of the Prandtl-number dependence without thermal radiation effects represents per se a detailed study of the radiation effects, too. In other words, the solution of the radiation problem for optically thick media in the linearized Rosseland approximation does not require any additional numerical or analytical effort compared to the same problem without radiation, making in this respect dozens of papers superfluous.     

Entwicklung und Erprobung eines Wäschersystems zur CO2‐Abreinigung aus Rauchgasen mithilfe alkalischer Reststoffe

An innovative, technical approach for the reduction of CO₂ emissions is presented that utilizes alkaline wastes to capture CO₂ from flue gases in stable mineral form. Comprehensive pilot‐scale experiments were conducted with the developed flue gas scrubbing system at a power plant site. By optimizing the process parameters gas flux, CO₂ partial pressure, circulation flux and suspension liquid‐to‐solid ratio, a CO₂ binding of 40 – 90 g kg^–1 waste could be reached and up to 25 % of the CO₂ could be captured. The new technique is economically advantageous especially when both alkaline waste and CO₂ are produced on site and when the carbonated products can be used as secondary resources.