Potassium deficiency,a “smart” cellular switch for sustained high yield hydrogen production by the green alga Scenedesmus obliquus

Hydrogen is considered to be the future optimal energy carrier, and is expected to contribute to the growth of the world's economy by facilitating a stable supply of energy. The ability of green algae to produce hydrogen was discovered 74 years ago. Since then, several attempts were made, to increase hydrogen production yields, sulfur starvation being the best known. The main concern during these attempts was that the achievable increase in yield was not sustainable. In this contribution, potassium deficiency is presented as a biochemical/bioenergetic switch for a sustained high yield of hydrogen production via the photosynthetic apparatus. Potassium can partially be replaced by sodium in the majority of biochemical processes and as a result the system remains functional. However, sodium cannot replace potassium in the conversion of glucose to starch. This fact significantly increased the yield of hydrogen production through the Photosystem II independent pathway, since electrons originating from the metabolism of glucose are used in the continuous donation to the plastoquinone-pool of the photosynthetic electron chain. Additionally, PSII inactivation (and therefore the inhibition of O₂-production), the further synthesis and over activation of Photosystem I and plastidic hydrogenase, generated a sustained increase in hydrogen production, mainly through the PSII-independent pathway. The self regulation of these multistage processes in hermitically closed static systems of Scenedesmus obliquus cultivation, permitted the establishment of anoxic conditions and the continuous electron supply to highly activated hydrogenase, resulting in the sustained high yield hydrogen production and paving the way for future usage in an industrial scale application.     

Variational Bayesian Image Restoration Based on a Product of t-Distributions Image Prior

Image priors based on products have been recognized to offer many advantages because they allow simultaneous enforcement of multiple constraints. However, they are inconvenient for Bayesian inference because it is hard to find their normalization constant in closed form. In this paper, a new Bayesian algorithm is proposed for the image restoration problem that bypasses this difficulty. An image prior is defined by imposing Student-t densities on the outputs of local convolutional filters. A variational methodology, with a constrained expectation step, is used to infer the restored image. Numerical experiments are shown that compare this methodology to previous ones and demonstrate its advantages.     

ERAP2 Inhibition Induces Cell-Surface Presentation by MOLT-4 Leukemia Cancer Cells of Many Novel and Potentially Antigenic Peptides

Recent studies have linked the activity of ER aminopeptidase 2 (ERAP2) to increased efficacy of immune-checkpoint inhibitor cancer immunotherapy, suggesting that pharmacological inhibition of ERAP2 could have important therapeutic implications. To explore the effects of ERAP2 inhibition on the immunopeptidome of cancer cells, we treated MOLT-4 T lymphoblast leukemia cells with a recently developed selective ERAP2 inhibitor, isolated Major Histocompatibility class I molecules (MHCI), and sequenced bound peptides by liquid chromatography tandem mass spectrometry. Inhibitor treatment induced significant shifts on the immunopeptidome so that more than 20% of detected peptides were either novel or significantly upregulated. Most of the inhibitor-induced peptides were 9mers and had sequence motifs and predicted affinity consistent with being optimal ligands for at least one of the MHCI alleles carried by MOLT-4 cells. Such inhibitor-induced peptides could serve as triggers for novel cytotoxic responses against cancer cells and synergize with the therapeutic effect of immune-checkpoint inhibitors.     

Characterization of mortars used for the construction of Saithidai Heroon Podium (1st century AD) in ancient Messene, Peloponnesus, Greece

The Saithidai Heroon Podium is a Mausoleum dated to the Roman Period located in ancient Messene, Peloponnesus, Greece. Its outer walls were constructed with porous and massive limestone blocks with no mortar in the joints. The core of the podium was filled by rock chips to angular boulders of sandstone, limestone, sand, gravel and earthy groundmass material. The groundmass is mostly composed of quartz and calcite, with minor amounts of clay minerals. Small, irregular lime lumps also occur, composed of authigenic euhedral calcite crystal assemblages and rare sub-microscopic quartz fragments, or rod-like CaO/SiO₂-rich mineral assemblages developed in pore spaces on fine-grained authigenic calcite crystals. The mortar used for the filling material of the Podium was poorly homogenized semi-hydraulic lime derived from the calcination of pure limestone and siliceous limestone fragments, possibly the waste material from the finishing of the building blocks of the Podium walls.     

Training Reinforcement Neurocontrollers Using the Polytope Algorithm

A new training algorithm is presented for delayed reinforcement learning problems that does not assume the existence of a critic model and employs the polytope optimization algorithm to adjust the weights of the action network so that a simple direct measure of the training performance is maximized. Experimental results from the application of the method to the pole balancing problem indicate improved training performance compared with critic-based and genetic reinforcement approaches.     

Kriechbeiwerte für die Berechnung von Verbundträgern

Creep factors for the computation of composite girders. Cross‐section properties, deformations and stresses in composite girders under consideration of creep and shrinkage are mainly calculated with the help of modular ratios. The application of this method demands the knowledge of creep factors, which take into account the long term behaviour of concrete and the time depended effects of the stresses in concrete. In literature there are different values for creep factors. In this article the precision of these factors and the influence of deviations are investigated. Proposals for the calculation procedure of creep and shrinkage effects are summarized.     

Effect of fortified milk on lyso‐platelet‐activating factor acetyltranferase and lipoprotein‐associated phospholipase A2 in hypercholesterolemic adults

Hypercholesterolemia is associated with subclinical inflammation, characterised by elevated proinflammatory mediators. Lyso‐platelet‐activating factor acetyltransferase (lyso‐PAF AT) and lipoprotein‐associated phospholipase A₂ (Lp‐PLA₂) are two key metabolic enzymes of platelet‐activating factor (PAF), a potent inflammatory lipid mediator. Little information is available concerning the efficacy of a dietary intervention on the metabolism of PAF. The objective of the study was to evaluate the effect of fortified milk on the activity of these enzymes. Forty‐three adults (mean age 49.8 ± 8.1 years) with body mass index <35 kg/m², and total cholesterol >200 but <310 mg/dL were randomised to two groups; (i) intervention group received 500 mL/day (two glasses) of a low‐fat milk fortified with phytosterols, linoleic and alpha linolenic acids, vitamin C, vitamin E, vitamin A, vitamin B6, vitamin B12, folic acid, magnesium and selenium (n = 22), and (ii) placebo group received 500 mL/day of a conventional low‐fat milk (n = 21) for 3 months. Outcome measures were the activities of lyso‐PAF AT from leukocytes and serum Lp‐PLA₂ determined with established methods. None of the activities changed significantly during the study in the intervention group, lyso‐PAF AT (95% confidence interval: ?1.7, 2.3 nmol/min/mg; p = 0.246), and Lp‐PLA₂ (?7.8, 5.8 nmol/min/mL, p = 0.591). No difference was observed between the two groups. In conclusion, daily intake of two glasses of phytosterols, antioxidants, linoleic and linolenic acids via fortified milk for three months had no effect on the activity of either lyso‐PAF AT or Lp‐PLA₂. Practical applications: Platelet‐activating factor (PAF) was the first intact phospholipid known to have messenger functions in which the signaling results from the molecule binding to specific receptors on the plasma membrane or other membranes of the cell. It has a number of pro‐inflammatory properties, and affects several critical points of atherogenesis including thrombosis, inflammation, and oxidation. Fortification of milk with nutrients that possess anti‐inflammatory properties and administration to adults with elevated blood cholesterol could provide a means to controlling inflammatory process through the synthesis and degradation of PAF in a population group at risk for cardiovascular morbidity and mortality.     

Preparation and characterization of lyophilised egg PC liposomes incorporating curcumin and evaluation of its activity against colorectal cancer cell lines

Curcumin has been associated with the treatment of various diseases in traditional medicine, among them cancer. The major problems that prevent its approval as therapeutic agent are its low water solubility and its relatively low in vivo bioavailability. Liposomes are considered as effective drug carriers because of their ability to solubilize hydrophobic compounds and to alter their pharmacokinetic properties. The purpose of this study was the development of lyophilised liposomal curcumin fully characterized in terms of its physical properties [(zeta-potential, size, size distribution and Polydispercity index (PI)], and to evaluate its in vitro cytotoxic against colorectal cancer cell lines in a short-term and in a long-term (clonogenic) assay. Curcumin was incorporated in egg-phosphatidylcholine (EPC) liposomes at a drug to lipid molar ratio 1:14 achieving high incorporation efficiency close to 85%. The liposomal curcumin was lyophilized preserving thus its stability. The reconstitution of the formulation resulted in the original liposomal suspension. The release in FBS showed a plateau near 14% at 96 hours of incubation. The in vitro studies against colorectal cancer cell lines have shown that liposomes improve the activity of curcumin especially in the long-term assay and the liposomal formulation found to be more potent against HCT116 and HCT15, cell lines which express the MDR phenotype. EPC liposomal curcumin in a molar ratio of curcumin/EPC 1:14 has shown improved cytotoxic activity versus free curcumin against colorectal cancer cell lines. In vivo studies based on the recent findings are in progress in our laboratory.