Distributed scheduling for disconnected cooperation

Ability to cooperate on common tasks in a distributed setting is key to solving a broad range of computation problems ranging from distributed search such as SETI to distributed simulation and multi-agent collaboration. In such settings there exists a trade-off between computation and communication: both resources must be managed to decrease redundant computation and to ensure efficient computational progress. This paper deals with scheduling issues for distributed collaboration. Specifically, we examine the extreme situation where initially collaboration must occur without communication. That is, we consider the extent to which efficient collaboration is possible if all resources are directed to computation at the expense of communication. The results summarized here precisely characterize the ability of distributed agents to collaborate on a known collection of independent tasks by means of local scheduling decisions that require no communication and that achieve low redundancy in task executions. Such scheduling solutions exhibit an interesting connection between the distributed collaboration problem and the design theory. The lower bounds presented here along with the randomized and deterministic schedule constructions show the limitations on such low-redundancy cooperation and show that schedules with near-optimal redundancy can be efficiently constructed by processors working in isolation. The work of G. Malewicz was done when he was a Ph.D. student at the University of Connecticut, and in part during a visit to the Specification and Algorithm Research Department, AT&T Shannon Lab, and the Supercomputing Technologies Group, Massachusetts Institute of Technology. Parts of this article appeared in a preliminary form in the Proceedings of the 14th International Symposium on Distributed Computing [24], Springer LNCS Vol. 1914, pp. 119–133, in the Proceedings of the 8th International Colloquium on Structural Information and Communication Complexity [23], and the doctoral thesis of the first author.     

Microstructure of the oxide ceramics/Inconel 713C interface

Nickel-based refractory alloys are used in the aerospace industry as materials for the production of engine turbine blades obtained by the casting method. Both casting process and surface quality of the ceramic mould have a significant influence on product properties. Current research involved the investigation of interactions between oxide ceramics, forming the basic material of casting moulds and crystallisers, and Inconel 713C nickel superalloy. The wettability of ceramics by Inconel 713C was tested for the three types of materials at temperatures commonly used in the directional casting of this alloy. The oxide ceramics/Inconel 713C interfaces were examined by SEM to reveal the microstructure of phase boundary and assess the degree of degradation of the casting mould ceramic coating.     

The influence of silver on the properties of cryptomelane type manganese oxides in N2O decomposition reaction

The cryptomelane type oxides were prepared by the redox precipitation technique using Mn(CH₃COO)₂ and KMnO₄ precursors. Nitrogen sorption, XRD, TEM and TPD of oxygen studies showed changes of the surface, structural and redox properties of the samples upon silver introduction. Samples were investigated in the N₂O decomposition reaction. Direct introduction of silver to the synthesis mixture caused partial distortion of regular channel-like structure of the oxides, leading to the decrease of Mn–O bonds strength. As results samples showed slightly better catalytic activity at low temperatures, but were less stable at high temperatures. An introduction of silver by the impregnation method caused the decrease of the surface area of the samples, increase of surface oxygen mobility, leading to the small changes of activity.     

Application of linear discriminant analysis in prostate cancer research by synchrotron radiation-induced X-ray emission

The ability to visualize an object of interest is one of the cornerstones of advancement in science. For this reason, synchrotron radiation-induced X-ray emission (micro-SRIXE) holds special promise as a imaging technique in structural biology, biochemistry, and medicine. It gives the possibility to image concentration of most of the elements in a sample at high space resolution. Statistical analysis of data obtained for samples of prostate tissues in an experiment at L-beam line HASYLAB (Hamburg, Germany) is presented in this paper. The regions for the measurements were selected according to the histological view of the sample. By histological examination, samples were divided into five groups (from healthy to Gleason4, most advanced stage of cancerogenesis). Data obtained in micro-SRIXE experiments on prostate cancer samples provide information about concentrations of certain elements in these groups. The rising problem is to find out concentrations of which elements allow the researcher to discriminate between different (early mentioned) groups. Linear discriminant analysis, a basic technique for feature extraction, was used in statistical analysis of the data. Our results indicate that the use of synchrotron radiation and discriminant analysis in the study of prostate cancer tissues provide information that can be key to better understanding of biomolecular functions.     

Structural ramification for acetyl-lysine recognition by the bromodomain of human BRG1 protein, a central ATPase of the SWI/SNF remodeling complex

Bromodomains represent an extensive family of evolutionarily conserved domains that are found in many chromatin-associated proteins such as histone acetyltransferases (HAT) and subunits of ATP-dependent chromatin-remodeling complexes. These domains are associated with acetylated lysine residues that bind both in vivo and in vitro; for example, they bind to the N-acetylated lysines of the histone tail of nucleosomes. In this report, we determined the structure of the bromodomain from human brahma-related gene 1 (BRG1) protein, a subunit of an ATP-dependent switching/sucrose nonfermenting (SWI/SNF) remodeling complex, and have also characterized its in vitro interaction with N-acetylated lysine peptides from histones. In addition to a typical all-alpha-helical fold that was observed in the bromodomains, we observed for the first time a small beta-sheet in the ZA loop region of the BRG1 protein. The BRG1 bromodomain exhibited binding, albeit weak, to acetylated peptides that were derived from histones H3 and H4. We have compared the acetyl-lysine binding sites of BRG1 bromodomain with the yGCN5 (general control of amino acid biosynthesis). By modeling the acetylated-lysine peptide into the BRG1 bromodomain structure, we were able to explain the weak binding of acetylated-lysine peptides to this bromodomain.     

Salt domes in Poland – Potential sites for hydrogen storage in caverns

Salt bearing formations have world-wide distribution. The geological structures of Permian salt bearing deposits in Poland are similar to those in the other parts of the Central European salt basin, to which they belong as its SE part. There is a notable trend to use salt domes as sites for underground storage of various gases, fuels and other substances, including hydrogen. Possibilities of using salt domes in Poland for underground hydrogen storage are presented with the focus on the option of using the underground space for energy storage. Usefulness of the 27 hitherto studied salt domes in the Polish Lowlands for underground hydrogen storage in caverns is evaluated using analytical methods of the geology of mineral deposits.Seven not yet developed salt domes are selected as the most promising ones, taking into account geological and reservoir criteria: Rogó?no, Damas?awek, Lubień, ?ani?ta, Goleniów, Izbica Kujawska and D?bina. Initial experience in underground hydrogen storage in salt caverns is presented. Geological conditions favourable for hydrogen storage in underground caverns leached in salt domes are outlined. Their advantage relative to underground storage sites in porous rocks (depleted hydrocarbon deposits and deep aquifers) is discussed.     

Memantine Modulates Oxidative Stress in the Rat Brain following Experimental Autoimmune Encephalomyelitis

Experimental autoimmune encephalomyelitis (EAE) is an animal model most commonly used in research on the pathomechanisms of multiple sclerosis (MS). The inflammatory processes, glutamate excitotoxicity, and oxidative stress have been proposed as determinants accompanying demyelination and neuronal degeneration during the course of MS/EAE. The aim of the current study was to characterize the role of NMDA receptors in the induction of oxidative stress during the course of EAE. The effect of memantine, the uncompetitive NMDA receptor antagonist, on modulation of neurological deficits and oxidative stress in EAE rats was analyzed using several experimental approaches. We demonstrated that the expression of antioxidative enzymes (superoxide dismutases SOD1 and SOD2) were elevated in EAE rat brains. Under the same experimental conditions, we observed alterations in oxidative stress markers such as increased levels of malondialdehyde (MDA) and decreased levels of sulfhydryl (-SH) groups, both protein and non-protein (indicating protein damage), and a decline in reduced glutathione. Importantly, pharmacological inhibition of ionotropic NMDA glutamate receptors by their antagonist memantine improved the physical activity of EAE rats, alleviated neurological deficits such as paralysis of tail and hind limbs, and modulated oxidative stress parameters (MDA, -SH groups, SOD’s). Furthermore, the current therapy aiming to suppress NMDAR-induced oxidative stress was partially effective when NMDAR’s antagonist was administered at an early (asymptomatic) stage of EAE.     

The Effect of Rotating Magnetic Field on Susceptibility Profile of Methicillin-Resistant Staphylococcus aureus Strains Exposed to Activity of Different Groups of Antibiotics

Methicillin-resistant strains of Staphylococcus aureus (MRSA) have become a global issue for healthcare systems due to their resistance to most β-lactam antibiotics, frequently accompanied by resistance to other classes of antibiotics. In this work, we analyzed the impact of combined use of rotating magnetic field (RMF) with various classes of antibiotics (β-lactams, glycopeptides, macrolides, lincosamides, aminoglycosides, tetracyclines, and fluoroquinolones) against nine S. aureus strains (eight methicillin-resistant and one methicillin-sensitive). The results indicated that the application of RMF combined with antibiotics interfering with cell walls (particularly with the β-lactam antibiotics) translate into favorable changes in staphylococcal growth inhibition zones or in minimal inhibitory concentration values compared to the control settings, which were unexposed to RMF. As an example, the MIC value of cefoxitin was reduced in all MRSA strains by up to 42 times. Apart from the β-lactams, the reduced MIC values were also found for erythromycin, clindamycin, and tetracycline (three strains), ciprofloxacin (one strain), gentamicin (six strains), and teicoplanin (seven strains). The results obtained with the use of in vitro biofilm model confirm that the disturbances caused by RMF in the bacterial cell walls increase the effectiveness of the antibiotics towards MRSA. Because the clinical demand for new therapeutic options effective against MRSA is undisputable, the outcomes and conclusions drawn from the present study may be considered an important road into the application of magnetic fields to fight infections caused by methicillin-resistant staphylococci.     

Targeting Energy Metabolism in Cancer Treatment

Cancer is the second most common cause of death worldwide after cardiovascular diseases. The development of molecular and biochemical techniques has expanded the knowledge of changes occurring in specific metabolic pathways of cancer cells. Increased aerobic glycolysis, the promotion of anaplerotic responses, and especially the dependence of cells on glutamine and fatty acid metabolism have become subjects of study. Despite many cancer treatment strategies, many patients with neoplastic diseases cannot be completely cured due to the development of resistance in cancer cells to currently used therapeutic approaches. It is now becoming a priority to develop new treatment strategies that are highly effective and have few side effects. In this review, we present the current knowledge of the enzymes involved in the different steps of glycolysis, the Krebs cycle, and the pentose phosphate pathway, and possible targeted therapies. The review also focuses on presenting the differences between cancer cells and normal cells in terms of metabolic phenotype. Knowledge of cancer cell metabolism is constantly evolving, and further research is needed to develop new strategies for anti-cancer therapies.