473 research outputs found
The modification of the energy spectrum of charged particles by exotic open 4-smoothness via superstring theory
In this paper we present a model where the modified Landau-like levels of
charged particles in a magnetic field are determined due to the modified
smoothness of as underlying structure of the Minkowski
spacetime. Then the standard smoothness of is shifted to the
exotic , , . This is achieved by
superstring theory using gravitational backreaction induced from a strong,
almost constant magnetic field on standard . The exact string
background containing flat is replaced consistently by the
curved geometry of as part of the modified exact
backgrounds. This corresponds to the change of smoothness on
from the standard to some exotic . The
calculations of the spectra are using the CFT marginal deformations and
Wess-Zumino-Witten (WZW) models. The marginal deformations capture the effects
of the magnetic field as well as its gravitational backreactions. The spectra
depend on even level of WZW on SU(2). At the same time the WZ term as
element of determines also the exotic smooth
. As the consequence we obtain a non-zero mass-gap emerges
in the spectrum induced from the presence of an exotic .Comment: 11 pages, Revtex4-1, will appear IJGMMP Vol. 50(1), 201
Exotic Smoothness and Quantum Gravity
Since the first work on exotic smoothness in physics, it was folklore to
assume a direct influence of exotic smoothness to quantum gravity. Thus, the
negative result of Duston (arXiv:0911.4068) was a surprise. A closer look into
the semi-classical approach uncovered the implicit assumption of a close
connection between geometry and smoothness structure. But both structures,
geometry and smoothness, are independent of each other. In this paper we
calculate the "smoothness structure" part of the path integral in quantum
gravity assuming that the "sum over geometries" is already given. For that
purpose we use the knot surgery of Fintushel and Stern applied to the class
E(n) of elliptic surfaces. We mainly focus our attention to the K3 surfaces
E(2). Then we assume that every exotic smoothness structure of the K3 surface
can be generated by knot or link surgery a la Fintushel and Stern. The results
are applied to the calculation of expectation values. Here we discuss the two
observables, volume and Wilson loop, for the construction of an exotic
4-manifold using the knot and the Whitehead link . By using Mostow
rigidity, we obtain a topological contribution to the expectation value of the
volume. Furthermore we obtain a justification of area quantization.Comment: 16 pages, 1 Figure, 1 Table subm. Class. Quant. Grav
Topological quantum D-branes and wild embeddings from exotic smooth R^4
This is the next step of uncovering the relation between string theory and
exotic smooth R^4. Exotic smoothness of R^4 is correlated with D6 brane charges
in IIA string theory. We construct wild embeddings of spheres and relate them
to a class of topological quantum Dp-branes as well to KK theory. These branes
emerge when there are non-trivial NS-NS H-fluxes where the topological classes
are determined by wild embeddings S^2 -> S^3. Then wild embeddings of higher
dimensional -complexes into S^n correspond to Dp-branes. These wild
embeddings as constructed by using gropes are basic objects to understand
exotic smoothness as well Casson handles. Next we build C*-algebras
corresponding to the embeddings. Finally we consider topological quantum
D-branes as those which emerge from wild embeddings in question. We construct
an action for these quantum D-branes and show that the classical limit agrees
with the Born-Infeld action such that flat branes = usual embeddings.Comment: 18 pages, 1 figur
Comparison of phase structures and surface free energy values for the coatings synthesised from linear polyurethanes and from waterborne polyurethane cationomers
WAXS, DSC and AFM methods were employed to compare phase structures of the coatings obtained from waterborne polyurethane cationomers which had been synthesised in the reaction of some diisocyanates (MDI, IPDI, TDI and HDI) with polyoxyethylene glycols (Mâ=â600 and 2,000) and butane1,4-diol or N-methyl- or N-butyldiethanolamine and 2,2,3,3-tetrafluoro-1,4-butanediol. The structures were also analysed of the coatings derived from linear polyurethanes which had been synthesised on the basis of similar raw materials. Better rigidity was found for generally amorphous cationomer coats. Changes were discussed in the surface free energy (SFE) values and in their components, as calculated independently with the use of the van OssâGood and OwensâWendt methods. Polyurethane coats turned out more hydrophobic as compared to cationomer ones. In both coat types, fluorine incorporated into cationomers contributed to lower SFE values: from 50 down to about 30Â mJ/m2
ChainSoft: Collaborative software development using smart contracts
In recent years, more and more companies require dedicated software to increase the efficiency of their business. However, with rapidly changing technologies it is often inefficient to maintain a dedicated team of developers. On the other hand, outsourcing software development requires considerable effort and trust between involved parties to ensure the quality of the code and adequate payment. We present ChainSoft - a platform for outsourcing software development and automatic payments between parties that distrust each other, by means of blockchain technology. ChainSoft allows any developer to create software and submit software, includes automatic code verification and enforce users' proper behavior. We implement our system using Ethereum Smart Contracts and Github/Travis CI and present first evaluation proving its security and low usage cost
Two bullets in the gun: combining immunotherapy with chemotherapy to defeat neuroblastoma by targeting adrenergic-mesenchymal plasticity
neuroblastoma (NB) is a childhood tumor that originates in the peripheral sympathetic nervous system and is responsible for 15% of cancer-related deaths in the pediatric population. Despite intensive multimodal treatment, many patients with high-risk NB relapse and develop a therapy-resistant tumor. one of the phenomena related to therapeutic resistance is intratumor heterogeneity resulting from the adaptation of tumor cells in response to different selective environmental pressures. The transcriptional and epigenetic profiling of NB tissue has recently revealed the existence of two distinct cellular identities in the NB, termed adrenergic (ADRN) and mesenchymal (MES), which can spontaneously interconvert through epigenetic regulation. this phenomenon, known as tumor plasticity, has a major impact on cancer pathogenesis. The aim of this review is to describe the peculiarities of these two cell states, and how their plasticity affects the response to current therapeutic treatments, with special focus on the immunogenic potential of MES cells. furthermore, we will discuss the opportunity to combine immunotherapy with chemotherapy to counteract NB phenotypic interconversion
Humoral and Cellular Response of Pheasants Vaccinated against Newcastle Disease and Haemorrhagic Enteritis
The purpose of the experiment was to define whether and to what extent can prophylactic vaccinations against Newcastle disease (ND) and haemorrhagic enteritis (HE) affect the humoral and cellular response in pheasants. The evaluation of humoral response was performed on a basis of agglutinin titre after administered antigen and the cellular immunity index was the delayed type hypersensitivity (DTH) reaction. The pheasants were prophylactically vaccinated against Newcastle Disease (ND) on the 1st, 28th and 56th day of life. Moreover, on the 49th day of life, part of the birds was given in the drinking water a vaccine containing the HEV (Haemorrhagic Enteritis Virus). Fourteen days after the HEV vaccination, the birds were intravenously given 0.5 ml of the 10% SRBC (sheep red blood cells) suspension. Simultaneously with the SRBC administration the delayed hypersensitivity test was performed by intradermal administration of phytohaemagglutinin (PHA). It was shown that in pheasants vaccinated with NDV and additionally with HEV, the specific agglutinin anti-SRBC titre was significantly (p < 0.05) lower than in birds vaccinated against ND only. It also appeared that, the antibodies resistant to 2-mercaptoethanol were 43% of the total pool of specific anti-SRBC antibodies in the NDV vaccinated birds, whereas in birds vaccinated also with HEV they were 75%. No significant differences were found in the DTH test. Only in the HEV vaccinated pheasants the tendency to increase the wing index value was noted. The results confirm the observations concerning immunosuppressive effects of simultaneous vaccinations. They also indicate that overloading the pheasants with many antigens (ND and HEV vaccination) may weaken the humoral response to administered SRBC
Density of Gr1-positive myeloid precursor cells, p-STAT3 expression and gene expression pattern in canine mammary cancer metastasis
The very recent studies on human and mice models have indicated an important role of myeloid precursor cells (progenitors or not fully differentiated cells that express the Gr1 antigen also called Gr1-positive myeloid suppressor cells) in the tumor progression and metastasis. They are thought to suppress the immune system and promote angiogenesis via Signal transducer and activator of transcription 3 (STAT3) activation. As of now there is no data available on the correlation of Gr1-positive cell number, phosphorylated STAT3 (p-STAT3) expression and cancer ability to metastasis. Thus, we counted the myeloid precursor cell number and analyzed p-STAT3 expression in 50 canine mammary tumors that gave local/distant metastases and did not metastasize. We showed that the number of Gr1-positive cells and p-STAT3 expression are significantly higher (pâ<â0.001) in the metastatic tumors than in the non-metastatic ones. We also observed higher expression of p-STAT3 in the canine mammary cancer cell lines with metastatic potential than in other cell lines (pâ<â0.001). Moreover, the number of myeloid precursors and p-STAT3 expression in metastatic tumors correlate strongly. The tumor infiltrating myeloid precursor cells may invigorate the STAT3 activity (probably via vascular endothelial growth factor â VEGF) that contributes to the tumor angiogenesis and furthermore tumor`s ability to metastasize. The analysis of gene expression in canine mammary cancer cell lines with metastatic potential indicated that semaphorin 3B (SEMA3B) and neuropilin receptors (NRP) may also be important elements in this process. Thus, we discuss the possible interactions within the tumor that may be required for cancer metastatis
- âŠ