35,319 research outputs found
Uncoupling of p97 ATPase activity has a dominant negative effect on protein extraction
p97 is a highly abundant, homohexameric AAA+ ATPase that performs a variety of essential cellular functions. Characterized as a ubiquitin-selective chaperone, p97 recognizes proteins conjugated to K48-linked polyubiquitin chains and promotes their removal from chromatin and other molecular complexes. Changes in p97 expression or activity are associated with the development of cancer and several related neurodegenerative disorders. Although pathogenic p97 mutations cluster in and around p97's ATPase domains, mutant proteins display normal or elevated ATPase activity. Here, we show that one of the most common p97 mutations (R155C) retains ATPase activity, but is functionally defective. p97-R155C can be recruited to ubiquitinated substrates on chromatin, but is unable to promote substrate removal. As a result, p97-R155C acts as a dominant negative, blocking protein extraction by a similar mechanism to that observed when p97's ATPase activity is inhibited or inactivated. However, unlike ATPase-deficient proteins, p97-R155C consumes excess ATP, which can hinder high-energy processes. Together, our results shed new insight into how pathogenic mutations in p97 alter its cellular function, with implications for understanding the etiology and treatment of p97-associated diseases
Probing neutrino and Higgs sectors in model with lepton-flavor non-universality
The neutrino and Higgs sectors in the \mbox{SU(2)}_1 \times \mbox{SU(2)}_2
\times \mbox{U(1)}_Y model with lepton-flavor non-universality are discussed.
We show that active neutrinos can get Majorana masses from radiative
corrections, after adding only new singly charged Higgs bosons. The mechanism
for generation of neutrino masses is the same as in the Zee models. This also
gives a hint to solving the dark matter problem based on similar ways discussed
recently in many radiative neutrino mass models with dark matter. Except the
active neutrinos, the appearance of singly charged Higgs bosons and dark matter
does not affect significantly the physical spectrum of all particles in the
original model. We indicate this point by investigating the Higgs sector in
both cases before and after singly charged scalars are added into it. Many
interesting properties of physical Higgs bosons, which were not shown
previously, are explored. In particular, the mass matrices of charged and
CP-odd Higgs fields are proportional to the coefficient of triple Higgs
coupling . The mass eigenstates and eigenvalues in the CP-even Higgs
sector are also presented. All couplings of the SM-like Higgs boson to normal
fermions and gauge bosons are different from the SM predictions by a factor
, which must satisfy the recent global fit of experimental data, namely
. We have analyzed a more general diagonalization of gauge boson
mass matrices, then we show that the ratio of the tangents of the and
mixing angles is exactly the cosine of the Weinberg angle, implying that
number of parameters is reduced by 1. Signals of new physics from decays of new
heavy fermions and Higgs bosons at LHC and constraints of their masses are also
discussed.Comment: 40 pages, 1 figure; Journal vesio
General one-loop formulas for decay
Radiative corrections to the are evaluated in the
one-loop approximation. The unitary gauge gauge is used. The analytic result is
expressed in terms of the Passarino-Veltman functions. The calculations are
applicable for the Standard Model as well for a wide class of its gauge
extensions. In particular, the decay width of a charged Higgs boson can be derived. The consistence of our formulas and
several specific earlier results is shown.Comment: 33 pages, 3 figures, a new section (V) and references were improved
in the published versio
The conceptual evolution of responsible research and innovation in China:A systematic literature review
Within the contemporary global economy, research and innovation are just as likely to come from non-western economic and political powers, such as China, as from western powers more traditionally associated with research and innovation production, such as in Europe and North America. Subsequently, how Responsible Research and Innovation (RRI) is conceptualised and applied in these alternative contexts is an important question. This review aims to contribute to a better understanding of the evolution and application of RRI in China by reviewing Chinese academic literature. Our analysis indicates that, on the one hand, there is wariness that a complete transplantation of a European conception of RRI to China might lead to cultural imperialism. On the other hand, it is hoped that RRI will improve the ethical governance of technological innovation in China. By analysing Chinese scholarship, the paper also attempts to define distinctive features of RRI in China.</p
Hubble space telescope STIS spectroscopy of the peculiar nova-like variables BK Lyn, V751 Cygni, and V380 Oph
We obtained Hubble STIS spectra of three nova-like variables: V751 Cygni, V380 Oph, and—the only confirmed nova-like variable known to be below the period gap—BK Lyn. In all three systems, the spectra were taken during high optical brightness state, and a luminous accretion disk dominates their far-ultraviolet (FUV) light. We assessed a lower limit of the distances by applying the infrared photometric method of Knigge. Within the limitations imposed by the poorly known system parameters (such as the inclination, white dwarf mass, and the applicability of steady state accretion disks) we obtained satisfactory fits to BK Lyn using optically thick accretion disk models with an accretion rate of for a white dwarf mass of Mwd = 1.2M and for Mwd = 0.4M. However, for the VY Scl-type nova-like variable V751 Cygni and for the SW Sex star V380 Oph, we are unable to obtain satisfactory synthetic spectral fits to the high state FUV spectra using optically thick steady state accretion disk models. The lack of FUV spectra information down to the Lyman limit hinders the extraction of information about the accreting white dwarf during the high states of these nova-like systems
Single Z' production at CLIC based on e^- gamma collisions
We analyze the potential of CLIC based on e- gamma collisions to search for
new gauge boson. Single Z' production at e-gamma colliders in two SU(3)_C
X SU(3)_L X U(1)_N models: the minimal model and the model with right-handed
(RH) neutrinos is studied in detail. Results show that new Z' gauge bosons can
be observed at the CLIC, and the cross sections in the model with RH neutrinos
are bigger than those in the minimal one.Comment: 11 pages, 4 figures, To appear in JET
Quartic Gauge Boson Couplings and Tree Unitarity in the SU(3)_C X SU(3)_L X U(1)_N Models
The quartic gauge boson couplings in the models are presented. We find that the couplings of four {\it
differrent} gauge bosons may have unusual Lorentz structure and the couplings
sastify the tree unitarity requirement at high energy limit.Comment: 13 pages, Latex, axodraw.st
Quantum-Mechanical Detection of Non-Newtonian Gravity
In this work the possibility of detecting the presence of a Yukawa term, as
an additional contribution to the usual Newtonian gravitational potential, is
introduced. The central idea is to analyze the effects at quantum level
employing interference patterns (at this respect the present proposal resembles
the Colella, Overhauser and Werner experiment), and deduce from it the possible
effects that this Yukawa term could have. We will prove that the corresponding
interference pattern depends on the phenomenological parameters that define
this kind of terms. Afterwards, using the so called restricted path integral
formalism, the case of a particle whose position is being continuously
monitored, is analyzed, and the effects that this Yukawa potential could have
on the measurement outputs are obtained. This allows us to obtain another
scheme that could lead to the detection of these terms. This last part also
renders new theoretical predictions that could enable us to confront the
restricted path integral formalism against some future experiments.Comment: 17 pages, accepted in International Journal of Modern Physics
Carbonate Hydroxyapatite and Silicon-Substituted Carbonate Hydroxyapatite: Synthesis, Mechanical Properties, and Solubility Evaluations
The present study investigates the chemical composition, solubility, and physical and mechanical properties of carbonate
hydroxyapatite (CO3Ap) and silicon-substituted carbonate hydroxyapatite (Si-CO3Ap) which have been prepared by a simple
precipitation method. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF)
spectroscopy, and inductively coupled plasma (ICP) techniques were used to characterize the formation of CO3Ap and Si-CO3Ap.
The results revealed that the silicate (SiO4
4−) and carbonate (CO3
2−) ions competed to occupy the phosphate (PO4
3−) site and also
entered simultaneously into the hydroxyapatite structure.TheSi-substitutedCO3Ap reduced the powder crystallinity and promoted
ion release which resulted in a better solubility compared to that of Si-free CO3Ap. The mean particle size of Si-CO3Ap was much
finer than that of CO3Ap. At 750∘C heat-treatment temperature, the diametral tensile strengths (DTS) of Si-CO3Ap and CO3Ap
were about 10.8 ± 0.3 and 11.8 ± 0.4 MPa, respectively
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