45 research outputs found
Glueball mass from quantized knot solitons and gauge-invariant gluon mass
We propose an approach which enables one to obtain simultaneously the
glueball mass and the gluon mass in the gauge-invariant way to shed new light
on the mass gap problem in Yang-Mills theory. First, we point out that the
Faddeev (Skyrme--Faddeev-Niemi) model can be induced through the
gauge-invariant vacuum condensate of mass dimension two from SU(2) Yang-Mills
theory. Second, we obtain the glueball mass spectrum by performing the
collective coordinate quantization of the topological knot soliton in the
Faddeev model. Third, we demonstrate that a relationship between the glueball
mass and the gluon mass is obtained, since the gauge-invariant gluon mass is
also induced from the relevant vacuum condensate. Finally, we determine
physical values of two parameters in the Faddeev model and give an estimate of
the relevant vacuum condensation in Yang-Mills theory. Our results indicate
that the Faddeev model can play the role of a low-energy effective theory of
the quantum SU(2) Yang-Mills theory.Comment: 17 pages, 2 figures, 3 tables; a version accepted for publication in
J. Phys. A: Math. Gen.; Sect. 2 and sect. 5 (old sect. 4) are modified. Sect.
4, Tables 1 and Table 3 are adde
Vortices on Orbifolds
The Abelian and non-Abelian vortices on orbifolds are investigated based on
the moduli matrix approach, which is a powerful method to deal with the BPS
equation. The moduli space and the vortex collision are discussed through the
moduli matrix as well as the regular space. It is also shown that a quiver
structure is found in the Kahler quotient, and a half of ADHM is obtained for
the vortex theory on the orbifolds as the case before orbifolding.Comment: 25 pages, 4 figures; references adde
Tyrosine kinase inhibitors reprogramming immunity in renal cell carcinoma: rethinking cancer immunotherapy
Review article[Abstract] The immune system regulates angiogenesis in cancer by way of both pro- and antiangiogenic activities. A bidirectional link between angiogenesis and the immune system has been clearly demonstrated. Most antiangiogenic molecules do not inhibit only VEGF signaling pathways but also other pathways which may affect immune system. Understanding of the role of these pathways in the regulation of immunosuppressive mechanisms by way of specific inhibitors is growing. Renal cell carcinoma (RCC) is an immunogenic tumor in which angiogenesis and immunosuppression work hand in hand, and its growth is associated with impaired antitumor immunity. Given the antitumor activity of selected TKIs in metastatic RCC (mRCC), it seems relevant to assess their effect on the immune system. The confirmation that TKIs improve cell cytokine response in mRCC provides a basis for the rational combination and sequential treatment of TKIs and immunotherapy
Increasing the bactofection capacity of a mammalian expression vector by removal of the f1 ori
Bacterial-mediated cancer therapy has shown great promise in in vivo tumour models with increased survival rates post-bacterial treatment. Improving efficiency of bacterial-mediated tumour regression has focused on controlling and exacerbating bacterial cytotoxicity towards tumours. One mechanism that has been used to carry this out is the process of bactofection where post-invasion, bacteria deliver plasmid-borne mammalian genes into target cells for expression. Here we utilised the cancer-targeting Salmonella Typhimurium strain, SL7207, to carry out bactofection into triple negative breast cancer MDA-MB-231 cells. However, we noted that post-transformation with the commonly used mammalian expression vector pEGFP, S. Typhimurium became filamentous, attenuated and unable to invade target cells efficiently. Filamentation did not occur in Escherichia coli-transformed with the same plasmid. Further investigation identified the region inducing S. Typhimurium filamentation as being the f1 origin of replication (f1 ori), an artefact of historic use of mammalian plasmids for single stranded DNA production. Other f1 ori-containing plasmids also induced the attenuated phenotype, while removal of the f1 ori from pEGFP restored S. Typhimurium virulence and increased the bactofection capacity. This work has implications for interpretation of prior bactofection studies employing f1 ori-containing plasmids in S. Typhimurium, while also indicating that future use of S. Typhimurium in targeting tumours should avoid the use of these plasmids
Folding in the Skyrme Model
There are only three stable singularities of a differentiable map between three-dimensional manifolds, namely folds, cusps and swallowtails. A Skyrme configuration is a map from space to SU(2), and its singularities correspond to the points where the baryon density vanishes. In this paper we consider the singularity structure of Skyrme configurations. The Skyrme model can only be solved numerically. However, there are good analytic ansaetze. The simplest of these, the rational map ansatz, has a non-generic singularity structure. This leads us to introduce a non-holomorphic ansatz as a generalization. For baryon number two, three and four, the approximate solutions derived from this ansatz are closer in energy to the true solutions than any other ansatz solution. We find that there is a tiny amount of negative baryon density for baryon number three, but none for two or four. We comment briefly on the relationship to Bogomolny-Prasad-Sommerfield monopoles
S(3) skyrmions and the rational map ansatz
This paper discusses multi-skyrmions on the 3-sphere with variable radius L using the rational map ansatz. For baryon number B = 3,...,9 this ansatz produces the lowest energy solutions known so far. By considering the geometry of the model we find an approximate analytic formula for the shape function. This provides an insight why skyrmions have a shell-like structure