Noncommutative elliptic theory. Examples

We study differential operators, whose coefficients define noncommutative algebras. As algebra of coefficients, we consider crossed products, corresponding to action of a discrete group on a smooth manifold. We give index formulas for Euler, signature and Dirac operators twisted by projections over the crossed product. Index of Connes operators on the noncommutative torus is computed.Comment: 23 pages, 1 figur

Assessment of adipokines, adenine nucleotides and uric acid in the dynamics of coronary intervention

Introduction: The association of vaspin and visfatin, with a myocardial infarction is still not fully understood. Reduced levels of adenine nucleotides are hallmarks of chronic heart failure. There is little data concerning the relationship between these markers and their changes over time. Material/Methods: The concentration of adenine nucleotides, vaspin and visfatinwere assessed in 41 consecutive patients with acute myocardial infarction one before (day I) and four days after (day IV) percutaneous coronary intervention (PCI) and a control group. Results: Visfatin concentrations were higher before and after PCI vs. control (visfatin I: median 25.55, 20.12 - 30.69 ng/ml; visfatin IV: median 20.79, 16.89 - 25.61 ng/ml vs. control: median 14.94, 10.66 - 25.25 ng/ml; p < 0.0001). Vaspin concentrations were lower before and after PCI vs. control (vaspin I: median 0.18, 0.11 - 0.44 ng/ml; vaspin IV: median 0.24, 0.15 - 0.58 ng/ml vs. control: median 1.303, 1.13 - 2.26 ng/ml, p < 0.00001). Concentrations of visfatin, day I, correlated well to vaspin concentrations (r2 = 0.201, p = 0.011). ATP levels were significantly lower in patients vs. controls (day I: p = 0.00012; day IV: p = 0.0001). Conclusions: Changes in the analyzed visfatin and vaspin concentrations can be used as potential MI markers. Visfatin serum concentration may be considered a potential marker to differentiate MI over time

DnaC Inactivation in Escherichia coli K-12 Induces the SOS Response and Expression of Nucleotide Biosynthesis Genes

Background: Initiation of chromosome replication in E. coli requires the DnaA and DnaC proteins and conditionally-lethal dnaA and dnaC mutants are often used to synchronize cell populations. Methodology/Principal Findings: DNA microarrays were used to measure mRNA steady-state levels in initiation-deficient dnaA46 and dnaC2 bacteria at permissive and non-permissive temperatures and their expression profiles were compared to MG1655 wildtype cells. For both mutants there was altered expression of genes involved in nucleotide biosynthesis at the non-permissive temperature. Transcription of the dnaA and dnaC genes was increased at the non-permissive temperature in the respective mutant strains indicating auto-regulation of both genes. Induction of the SOS regulon was observed in dnaC2 cells at 38uC and 42uC. Flow cytometric analysis revealed that dnaC2 mutant cells at non-permissive temperature had completed the early stages of chromosome replication initiation. Conclusion/Significance: We suggest that in dnaC2 cells the SOS response is triggered by persistent open-complex formation at oriC and/or by arrested forks that require DnaC for replication restart

Retrograde traffic in the biosynthetic-secretory route

In the biosynthetic-secretory route from the rough endoplasmic reticulum, across the pre-Golgi intermediate compartments, the Golgi apparatus stacks, trans Golgi network, and post-Golgi organelles, anterograde transport is accompanied and counterbalanced by retrograde traffic of both membranes and contents. In the physiologic dynamics of cells, retrograde flow is necessary for retrieval of molecules that escaped from their compartments of function, for keeping the compartments’ balances, and maintenance of the functional integrities of organelles and compartments along the secretory route, for repeated use of molecules, and molecule repair. Internalized molecules may be transported in retrograde direction along certain sections of the secretory route, and compartments and machineries of the secretory pathway may be misused by toxins. An important example is the toxin of Shigella dysenteriae, which has been shown to travel from the cell surface across endosomes, and the Golgi apparatus en route to the endoplasmic reticulum, and the cytosol, where it exerts its deleterious effects. Most importantly in medical research, knowledge about the retrograde cellular pathways is increasingly being utilized for the development of strategies for targeted delivery of drugs to the interior of cells. Multiple details about the molecular transport machineries involved in retrograde traffic are known; a high number of the molecular constituents have been characterized, and the complicated fine structural architectures of the compartments involved become more and more visible. However, multiple contradictions exist, and already established traffic models again are in question by contradictory results obtained with diverse cell systems, and/or different techniques. Additional problems arise by the fact that the conditions used in the experimental protocols frequently do not reflect the physiologic situations of the cells. Regular and pathologic situations often are intermingled, and experimental treatments by themselves change cell organizations. This review addresses physiologic and pathologic situations, tries to correlate results obtained by different cell biologic techniques, and asks questions, which may be the basis and starting point for further investigations

Nuclear Magnetic Resonance metabolomics reveals an excretory metabolic signature of renal cell carcinoma

RCC usually develops and progresses asymptomatically and, when detected, it is frequently at advanced stages and metastatic, entailing a dismal prognosis. Therefore, there is an obvious demand for new strategies enabling an earlier diagnosis. The importance of metabolic rearrangements for carcinogenesis unlocked a new approach for cancer research, catalyzing the increased use of metabolomics. The present study aimed the NMR metabolic profiling of RCC in urine samples from a cohort of RCC patients (n = 42) and controls (n = 49). The methodology entailed variable selection of the spectra in tandem with multivariate analysis and validation procedures. The retrieval of a disease signature was preceded by a systematic evaluation of the impacts of subject age, gender, BMI, and smoking habits. The impact of confounders on the urine metabolomics profile of this population is residual compared to that of RCC. A 32-metabolite/resonance signature descriptive of RCC was unveiled, successfully distinguishing RCC patients from controls in principal component analysis. This work demonstrates the value of a systematic metabolomics workflow for the identification of robust urinary metabolic biomarkers of RCC. Future studies should entail the validation of the 32-metabolite/resonance signature found for RCC in independent cohorts, as well as biological validation of the putative hypotheses advanced

Comment on "Comparative study on earthquake and ground based transmitter induced radiation belt electron precipitation at middle latitude" by Sideropoulos et al. (2011)

Denne artikel er et forsøg på at knytte den traditionelle tekstbaserede humanistiske læring på universitetet til informationshåndterende aktiviteter som fx litteratursøgning. Der tages udgangspunkt i en kognitiv-kon­struk­tivistisk læringsforståelse under decideret henvisning til dens individuel-kognitive og gruppemæssig-sociale elementer. Både selve tekstforståelsen og dynamikken mellem forståelsesbaserede og teksthåndterende aktiviteter konciperes cyklisk. Tekstforståelse som læringsaktivitet består i cykliske skift mellem en individuel, kognitiv bearbejdelse af stoffet og en kommunikativ afprøvning af den opnåede viden i den lærende gruppe. Overgangen mellem forståelsesorienteret læring og tekstsøgning er ligesom cyklisk struktureret, da informationssøgningsaktiviteter både tager afsæt fra og peger hen imod en fordybet tekstforståelse, idet al meningsfuld håndtering af information, udvidelse eller vinkling baserer sig på en forudgående forståelse af udgangstekster. Samtidig leder alle informationssøgningsaktiviteter hen til en ny forståelse, hvor udvidelsen/vinklingen intellektuelt forarbejdes i en ny runde af forstående læsning. Hovedsigtet med denne artikel er at pege på dynamikken i en iterativ universitetspædagogisk læringsmodel, hvor tekstforståelse og ‑håndtering skifter med hinanden i en, for den lærende, meningsfyldt sekvens. Dette har bl.a. den pædagogiske konsekvens, at man allerede i undervisningen bør tilstræbe ikke at begrænse læring til tekstforstående aktiviteter alene, men at placere dem i undervisningen på en didaktisk vis i en frugtbar læringsmæssig sammenhæng med informationshåndterende aktiviteter.  This article is an attempt to link traditional text-based and humanistic learning at a higher educational level to information managing activities such as information search. The starting point is a cognitive-constructivist understanding of learning, with an emphasis on its individual-cognitive and group-based social elements. How students understand a text and the dynamics of understanding and text managing activities are modeled cyclically. Text understanding as the basic learning activity consists of cyclic shifts between an individual, cognitive processing of the material and a communicative testing of the achieved knowledge in the learning community. The transitions between understanding-oriented learning and text search are structured cyclically as well, since information search activities are both based on and point to a deepened text understanding: Meaningful management of information rests on a previous understanding of texts; at the same time, information seeking activities lead to a new understanding, where the elaborated text collection is intellectually processed in a new round of reading. This paper discusses the results of a study which was able to identify the dynamics for an iterative pedagogical learning model typical of higher education, where the learning individual’s text understanding and text management alternate in a meaningful sequence. This supports pedagogical theories that suggest teaching should not focus on text understanding activities alone, but combine such understanding with information management activities.</p

Oxidized low-density lipoproteins enhance expression and activity of CD39 and CD73 in the human aortic valve endothelium.

Extracellular nucleotides regulate thrombosis, inflammation and immune response. Ectonucleoside triphosphate diphosphohydrolase 1 (CD39) and ecto-5'-nucleotidase (CD73) convert extracellular nucleotides in a sequential order: ATP to ADP, AMP and then to adenosine. In this study, we aimed to test an effect of oxidized LDL (ox-LDL) on CD39 and CD73 in endothelial cells. Human aortic valve endothelial cells were exposed to oxidized low-density lipoprotein, for 24-48 h. Next, the activity, protein expression and mRNA transcripts level of CD39 and CD73 were characterised by: an incubation with ATP or AMP followed by HPLC analysis of media as well as western blots and qPCR. Results are presented as mean ± SEM. CD73 activity in human valve endothelial cells was increased in presence of ox-LDL (4.04±0.32 nmol/mg prot./min) as compared to control (2.75±0.21 nmol/mg prot/min). There was almost no effect of ox-LDL on CD39 activity. A similar effect was observed for mRNA and protein expression. In conclusion, we found that ox-LDL modulated CD39 and CD73 activity in the endothelium, which may contribute to relevant pathologies and featured treatments

Thermophysical and chemical properties of perennial energy crops depending on harvest period

This paper presents analyses of the thermophysical and chemical properties of eleven perennial crop species harvested in one-year rotation cycles. The crops included four species grown for biomass in the form of straw, five species producing semi-wood biomass, and two species yielding wood biomass. The research comprised three consecutive crop harvests. In each harvesting season, biomass samples for analyses were taken on six dates at one-month intervals. Thermophysical and chemical properties of the biomass were significantly differentiated within the main experimental factors and their interactions. The biomass produced by Virginia mallow had the best quality parameters as solid fuel. In fact, it achieved the lowest water content and the highest lower heating value during all of the analyzed seasons and harvest dates. The biomass of the species yielding straw or semi-wood products attained better quality as solid fuel on later harvest dates. In turn, the quality of willow biomass remained practically unchanged between the harvest dates