391 research outputs found
Induced low-energy effective action in the 6D, N=(1,0) hypermultiplet theory on the vector multiplet background
We consider the six dimensional N=(1,0) hypermultiplet model coupled to an
external field of the Abelian vector multiplet in harmonic superspace approach.
Using the superfield proper-time technique we find the divergent part of the
effective action and derive the complete finite induced low-energy superfield
effective action. This effective action depends on external field and contains
in bosonic sector all the powers of the constant Maxwell field strength. The
obtained result can be treated as the 6D, N=(1,0) supersymmetric
Heisenberg-Euler type effective action.Comment: 15 pages; v2: minor correction
Quantum Equivalence of Massive Antisymmetric Tensor Field Models in Curved Space
We study the effective actions for massive rank-2 and rank-3 antisymmetric
tensor field models in curved space-time. These models are classically
equivalent to massive vector field and massive scalar field with minimal
coupling to gravity respectively. We prove that effective action for massive
rank-2 antisymmetric tensor field is exactly equal to one for massive vector
field and effective action for massive rank-3 antisymmetric tensor field is
exactly equal to one for massive scalar field. Prove is based on an identity
for mass-dependent zeta-functions associated with Laplacians acting on
-forms.Comment: 8 pages, REVTeX fil
Development of technology for deposition of thick copper layers onto ceramic substrates applied in power electronics
The basic element of the design of a power module is a metallized ceramic substrate. In this work, the formation of metallization coatings by the method of thermal transfer of metallization pastes (Mo-Mn-Si + binder) for alumina and aluminum nitride ceramics was carried out. The fixing of the metallization coating on the ceramic substrate was performed by firing at a temperature of 1320 °C. The subsequent deposition of the copper layer was carried out by the method of cold gas-dynamic spraying (CGDS) followed by annealing of the deposited coating. For high-quality adhesion, the optimum annealing temperature was 1000 °C
Application of the programmable logic controller GLOFA-GM7 in industry
The paper discusses the application of PLC in industry and also the different parts of typical scheme and methods of connection it and programming. The paper is provided with 5 figures
Smallest near-infrared fluorescent protein evolved from cyanobacteriochrome as versatile tag for spectral multiplexing
From a single domain of cyanobacteriochrome (CBCR) we developed a near-infrared (NIR) fluorescent protein (FP), termed miRFP670nano, with excitation at 645 nm and emission at 670 nm. This is the first CBCR-derived NIR FP evolved to efficiently bind endogenous biliverdin chromophore and brightly fluoresce in mammalian cells. miRFP670nano is a monomer with molecular weight of 17 kDa that is 2-fold smaller than bacterial phytochrome (BphP)-based NIR FPs and 1.6-fold smaller than GFP-like FPs. Crystal structure of the CBCR-based NIR FP with biliverdin reveals a molecular basis of its spectral and biochemical properties. Unlike BphP-derived NIR FPs, miRFP670nano is highly stable to denaturation and degradation and can be used as an internal protein tag. miRFP670nano is an effective FRET donor for red-shifted NIR FPs, enabling engineering NIR FRET biosensors spectrally compatible with GFP-like FPs and blue-green optogenetic tools. miRFP670nano unlocks a new source of diverse CBCR templates for NIR FPs.Peer reviewe
Chiral effective potential in non-commutative Wess-Zumino model
We study a structure of holomorphic quantum contributions to the effective
action for noncommutative Wess-Zumino model. Using the symbol
operator techniques we present the one-loop chiral effective potential in a
form of integral over proper time of the appropriate heat kernel. We prove that
this kernel can be exactly found. As a result we obtain the exact integral
representation of the one-loop effective potential. Also we study the expansion
of the effective potential in a series in powers of the chiral superfield
and derivative and construct a procedure for systematic
calculation of the coefficients in the series. We show that all terms in the
series without derivatives can be summed up in an explicit form.Comment: LaTeX, JHEP style, 32 pages, typos corrected, references adde
Single-domain near-infrared protein provides a scaffold for antigen-dependent fluorescent nanobodies
miRFP670nano3 offers improved near-infrared imaging and was used to develop fluorescent nanobodies whose stability and fluorescence strongly depend on antigen binding, with broad implications for detecting and manipulating cellular targets. Small near-infrared (NIR) fluorescent proteins (FPs) are much needed as protein tags for imaging applications. We developed a 17 kDa NIR FP, called miRFP670nano3, which brightly fluoresces in mammalian cells and enables deep-brain imaging. By exploring miRFP670nano3 as an internal tag, we engineered 32 kDa NIR fluorescent nanobodies, termed NIR-Fbs, whose stability and fluorescence strongly depend on the presence of specific intracellular antigens. NIR-Fbs allowed background-free visualization of endogenous proteins, detection of viral antigens, labeling of cells expressing target molecules and identification of double-positive cell populations with bispecific NIR-Fbs against two antigens. Applying NIR-Fbs as destabilizing fusion partners, we developed molecular tools for directed degradation of targeted proteins, controllable protein expression and modulation of enzymatic activities. Altogether, NIR-Fbs enable the detection and manipulation of a variety of cellular processes based on the intracellular protein profile.Peer reviewe
Effective action of three-dimensional extended supersymmetric matter on gauge superfield background
We study the low-energy effective actions for gauge superfields induced by
quantum N=2 and N=4 supersymmetric matter fields in three-dimensional Minkowski
space. Analyzing the superconformal invariants in the N=2 superspace we propose
a general form of the N=2 gauge invariant and superconformal effective action.
The leading terms in this action are fixed by the symmetry up to the
coefficients while the higher order terms with respect to the Maxwell field
strength are found up to one arbitrary function of quasi-primary N=2
superfields constructed from the superfield strength and its covariant spinor
derivatives. Then we find this function and the coefficients by direct quantum
computations in the N=2 superspace. The effective action of N=4 gauge multiplet
is obtained by generalizing the N=2 effective action.Comment: 1+27 pages; v2: minor corrections, references adde
Gauge invariant derivative expansion of the effective action at finite temperature and density and the scalar field in 2+1 dimensions
A method is presented for the computation of the one-loop effective action at
finite temperature and density. The method is based on an expansion in the
number of spatial covariant derivatives. It applies to general background field
configurations with arbitrary internal symmetry group and space-time
dependence. Full invariance under small and large gauge transformations is
preserved without assuming stationary or Abelian fields nor fixing the gauge.
The method is applied to the computation of the effective action of spin zero
particles in 2+1 dimensions at finite temperature and density and in presence
of background gauge fields. The calculation is carried out through second order
in the number of spatial covariant derivatives. Some limiting cases are worked
out.Comment: 34 pages, REVTEX, no figures. Further comments adde
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