2,576 research outputs found
Human Cytomegalovirus glycoprotein UL16 causes intracellular sequestration of NKG2D ligands, protecting against NK cell cytotoxicity.
The activating receptor, NKG2D, is expressed on a variety of immune effector cells and recognizes divergent families of major histocompatibility complex (MHC) class I-related ligands, including the MIC and ULBP proteins. Infection, stress, or transformation can induce NKG2D ligand expression, resulting in effector cell activation and killing of the ligand-expressing target cell. The human cytomegalovirus (HCMV) membrane glycoprotein, UL16, binds to three of the five known ligands for human NKG2D. UL16 is retained in the endoplasmic reticulum and cis-Golgi apparatus of cells and causes MICB to be similarly retained and stabilized within cells. Coexpression of UL16 markedly reduces cell surface levels of MICB, ULBP1, and ULBP2, and decreases susceptibility to natural killer cell-mediated cytotoxicity. Domain swapping experiments demonstrate that the transmembrane and cytoplasmic domains of UL16 are important for intracellular retention of UL16, whereas the ectodomain of UL16 participates in down-regulation of NKG2D ligands. The intracellular sequestration of NKG2D ligands by UL16 represents a novel HCMV immune evasion mechanism to add to the well-documented viral strategies directed against antigen presentation by classical MHC molecules
Mamdani-Fuzzy Modeling Approach for Quality Prediction of Non-Linear Laser Lathing Process
Lathing is a process to fashioning stock materials into desired cylindrical shapes which usually performed by traditional lathe machine. But, the recent rapid advancements in engineering materials and precision demand gives a great challenge to the traditional method.
The main drawback of conventional lathe is its mechanical contact which brings to the undesirable tool wear, heat affected zone, finishing, and dimensional accuracy especially taper quality in machining of stock with high length to diameter ratio. Therefore, a novel approach has
been devised to investigate in transforming a 2D flatbed CO2 laser cutting machine into 3D laser
lathing capability as an alternative solution. Three significant design parameters were selected
for this experiment, namely cutting speed, spinning speed, and depth of cut. Total of 24
experiments were performed with eight (8) sequential runs where they were then replicated three
(3) times. The experimental results were then used to establish Mamdani - Fuzzy predictive
model where it yields the accuracy of more than 95%. Thus, the proposed Mamdani-Fuzzy modeling approach is found very much suitable and practical for quality prediction of non-linear laser lathing process for cylindrical stocks of 10mm diameter
Interpolating Coherent States for Heisenberg-Weyl and Single-Photon SU(1,1) Algebras
New quantal states which interpolate between the coherent states of the
Heisenberg_Weyl and SU(1,1) algebras are introduced. The interpolating states
are obtained as the coherent states of a closed and symmetric algebra which
interpolates between the two algebras. The overcompleteness of the
interpolating coherent states is established. Differential operator
representations in suitable spaces of entire functions are given for the
generators of the algebra. A nonsymmetric set of operators to realize the
Heisenberg-Weyl algebra is provided and the relevant coherent states are
studied.Comment: 13 pages nd 5 ps figure
Photon-added coherent states as nonlinear coherent states
The states , defined as up to a
normalization constant and is a nonnegative integer, are shown to be the
eigenstates of where is a nonlinear
function of the number operator . The explicit form of
is constructed. The eigenstates of this operator for negative values of are
introduced. The properties of these states are discussed and compared with
those of the state .Comment: Rev Tex file with two figures as postscript files attached. Email:
[email protected]
The Central Charge of the Warped AdS^3 Black Hole
The AdS/CFT conjecture offers the possibility of a quantum description for a
black hole in terms of a CFT. This has led to the study of general AdS^3 type
black holes with a view to constructing an explicit toy quantum black hole
model. Such a CFT description would be characterized by its central charge and
the dimensions of its primary fields. Recently the expression for the central
charges (C_L, C_R) of the CFT dual to the warped AdS^3 have been determined
using asymptotic symmetry arguments. The central charges depend, as expected,
on the warping factor. We show that topological arguments, used by Witten to
constrain central charges for the BTZ black hole, can be generalized to deal
with the warped AdS^3 case. Topology constrains the warped factor to be
rational numbers while quasinormal modes are conjectured to give the dimensions
of primary fields. We find that in the limit when warping is large or when it
takes special rational values the system tends to Witten's conjectured unique
CFT's with central charges that are multiples of 24.Comment: 6 pages, Latex fil
Schr\"{o}dinger cat state of trapped ions in harmonic and anharmonic oscillator traps
We examine the time evolution of a two level ion interacting with a light
field in harmonic oscillator trap and in a trap with anharmonicities. The
anharmonicities of the trap are quantified in terms of the deformation
parameter characterizing the q-analog of the harmonic oscillator trap.
Initially the ion is prepared in a Schr\"{o}dinger cat state. The entanglement
of the center of mass motional states and the internal degrees of freedom of
the ion results in characteristic collapse and revival pattern. We calculate
numerically the population inversion I(t), quasi-probabilities and
partial mutual quantum entropy S(P), for the system as a function of time.
Interestingly, small deformations of the trap enhance the contrast between
population inversion collapse and revival peaks as compared to the zero
deformation case. For \beta =3 and determines the average number
of trap quanta linked to center of mass motion) the best collapse and revival
sequence is obtained for \tau =0.0047 and \tau =0.004 respectively. For large
values of \tau decoherence sets in accompanied by loss of amplitude of
population inversion and for \tau \sim 0.1 the collapse and revival phenomenon
disappear. Each collapse or revival of population inversion is characterized by
a peak in S(P) versus t plot. During the transition from collapse to revival
and vice-versa we have minimum mutual entropy value that is S(P)=0. Successive
revival peaks show a lowering of the local maximum point indicating a
dissipative irreversible change in the ionic state. Improved definition of
collapse and revival pattern as the anharminicity of the trapping potential
increases is also reflected in the Quasi- probability versus t plots.Comment: Revised version, 16 pages,6 figures. Revte
MoTe2 : An uncompensated semimetal with extremely large magnetoresistance
Transition-metal dichalcogenides (WTe and MoTe) have drawn much
attention, recently, because of the nonsaturating extremely large
magnetoresistance (XMR) observed in these compounds in addition to the
predictions of likely type-II Weyl semimetals. Contrary to the topological
insulators or Dirac semimetals where XMR is linearly dependent on the field, in
WTe and MoTe the XMR is nonlinearly dependent on the field, suggesting
an entirely different mechanism. Electron-hole compensation has been proposed
as a mechanism of this nonsaturating XMR in WTe, while it is yet to be
clear in the case of MoTe which has an identical crystal structure of
WTe at low temperatures. In this paper, we report low-energy electronic
structure and Fermi surface topology of MoTe using angle-resolved
photoemission spectrometry (ARPES) technique and first-principle calculations,
and compare them with that of WTe to understand the mechanism of XMR. Our
measurements demonstrate that MoTe is an uncompensated semimetal, contrary
to WTe in which compensated electron-hole pockets have been identified,
ruling out the applicability of charge compensation theory for the
nonsaturating XMR in MoTe. In this context, we also discuss the
applicability of the existing other conjectures on the XMR of these compounds.Comment: 9 pages, 6 fig
A multi-specialty surgical course for residents transitioning from early to intermediate training.
Supersymmetry, Shape Invariance and Solvability of and Calogero-Sutherland Model
Using the ideas of supersymmetry and shape invariance we re-derive the
spectrum of the and Calogero-Sutherland model. We briefly
discuss as to how to obtain the corresponding eigenfunctions. We also discuss
the difficulties involved in extending this approach to the trigonometric
models.Comment: 15 pages, REVTeX,No figure
Chiral Solitons in a Current Coupled Schr\"odinger Equation With Self Interaction
Recently non-topological chiral soliton solutions were obtained in a
derivatively coupled non-linear Schr\"odinger model in 1+1 dimensions. We
extend the analysis to include a more general self-coupling potential (which
includes the previous cases) and find chiral soliton solutions. Interestingly
even the magnitude of the velocity is found to be fixed. Energy and U(1) charge
associated with this non-topological chiral solitons are also obtained.Comment: 8 pages, no figure, to appear in Phys. Rev.
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