Split Pair Research Articles

Comparison of the sensitivity of conventional cytology and the ThinPrep Imaging System for 1,083 biopsy confirmed high‐grade squamous lesions

Liquid-based cytology continues to be utilized as an adjunct to conventional cytology in most Australian laboratories, even though a direct-to-vial ThinPrep protocol has been introduced in many countries with established cervical screening programs. Manual screening of ThinPrep slides has been widely practiced for more than 10 years and the recent introduction of the ThinPrep Imaging System (TPI) has been reported as being more sensitive than the conventional smear (CS) in the identification of high-grade cervical disease.We report our experience with ThinPrep Imaging since its introduction into our routine gynecological cytology service. 87,284 split sample pairs reported using the Imaging System demonstrated a decrease in unsatisfactory reports (3.65% for CS and 0.87% for TPI) and an increase in possible high grade and definite high-grade squamous reports (1.57% for CS and 1.62% for TPI).For 1,083 biopsy confirmed high-grade lesions, the correct diagnosis of high grade or possible high-grade squamous disease was made on the ThinPrep imaged slide in 61.0% (661/1,083) of cases and on the CS in 59.4% (643/1,083). This was not statistically significant. When all abnormalities identified on cytology were considered, including possible low grade and definite low-grade abnormalities, the difference in sensitivity for Thinprep imaged slides of 96.0% (1,040/1,083) and CSs of 91.6% (992/1,083) was statistically significant.

Resonant Tunneling in Photonic Double Quantum Well Heterostructures.

Here, we study the resonant photonic states of photonic double quantum well (PDQW) heterostructures composed of two different photonic crystals. The heterostructure is denoted as B/A/B/A/B, where photonic crystals A and B act as photonic wells and barriers, respectively. The resulting band structure causes photons to become confined within the wells, where they occupy discrete quantized states. We have obtained an expression for the transmission coefficient of the PDQW heterostructure using the transfer matrix method and have found that resonant states exist within the photonic wells. These resonant states occur in split pairs, due to a coupling between degenerate states shared by each of the photonic wells. It is observed that when the resonance energy lies at a bound photonic state and the two photonic quantum wells are far away from each other, resonant states appear in the transmission spectrum of the PDQW as single peaks. However, when the wells are brought closer together, coupling between bound photonic states causes an energy-splitting effect, and the transmitted states each have two peaks. Essentially, this means that the system can be switched between single and double transparent states. We have also observed that the total number of resonant states can be controlled by varying the width of the photonic wells, and the quality factor of transmitted peaks can be drastically improved by increasing the thickness of the outer photonic barriers. It is anticipated that the resonant states described here can be used to develop new types of photonic-switching devices, optical filters, and other optoelectronic devices.

Structural Clones of UAG Decoding RNA

Functions of non-coding RNAs are related in part to their secondary structures. We investigate the uniqueness of the secondary structure of a non-coding RNA (ncRNA) decoding UAG to read pyrrolysine (pyl). Nineteen archaeal methanogens are searched with our tRNA-pyl-tracker, TPYLT, perl-script downloadable from www.gyanxet.com. We observe that aside from the usual pyl-gene-cluster, pyl-carrying Methanosarcinaceae have a good number of conjugate-halves from pyl-tRNA (pylT) gene split at 37/38 spread over their genomes. On insilico ligation, the secondary structures of these pairs clone the clover-leaf of pylT of M. barkeri. Of these nineteen methanogens, four, namely, M. stadtmanae, M. kandleri, M. hungatei, and M. thermautotrophicus, have these pairs at levels at or higher than in the pyl-carrying ones. Screening these we arrive at four pairs, i.e., one from each of these four genomes. On ligation, these are close homologs of pylT gene of M. barkeri. The intervening sequences between the split pairs in these four cases are shown to nearly reproduce the known secondary structures at exon-intron boundaries.

Electron paramagnetic resonance studies of nitrogen interstitial defects in diamond

We report on electron paramagnetic resonance (EPR) studies of nitrogen doped diamond that hasbeen 15N enriched, electron irradiated and annealed. EPR spectra from two new nitrogen containing defects are detected and labelled WAR9 and WAR10. We show thatthe properties of these defects are consistent with them being the⟨001⟩-nitrogen split interstitialand the ⟨001⟩-nitrogensplit interstitial–⟨001⟩-carbon split interstitial pair, respectively. We also provide an explanation for why thesedefects have previously eluded discovery.

HTS 5 Tesla Synchrotron and Neutron Beamline Magnets

Two world-first High-Tc Superconducting (HTS) beamline magnets have been designed, manufactured and commissioned for synchrotron and neutron research facilities. One, for the Hahn-Meitner Institut, is for use with their high-resolution diffraction and resonant magnetic scattering instrument MAGS at the Berlin electron synchrotron facility BESSY. The key features of this 5 tesla split-pair magnet include field performance within a given confined geometry, and low weight. Mounting in a 6-circle goniometer and employing conduction-cooled HTS coils, it operates through 90 degrees of rotation with respect to the beamline axis and scattering plane. The neutron beamline magnet is also a 5 tesla split pair, designed for both neutron reflectometry and small-angle neutron scattering research at the new OPAL neutron facility of the Australian Nuclear Science and Technology Organisation. This much larger magnet offers wide neutron beam accessibility angles in both axial and transverse directions, large (50 mm) sample capability, and mounts on tilt stages operating in two axes. Both magnets use pulse-tube refrigeration for the HTS coils, which have been constructed from high performance BSCCO wire, and both are compatible with separate commercial cryofurnaces providing sample temperatures from 1.5 K (MAGS) or 4 K (OPAL) to over 600 K.

Development Trends in High Field Magnet Technology

The production of high magnetic fields using low temperature superconductors (LTS) has become common place. However, large magnet sizes and associated high cooling costs have often precluded the full utilization of these research capabilities. Recent advances in internal Sn superconductors and cryogen free technology have opened up a new era in superconducting magnet development. Ultra-compact, laboratory sized magnets producing fields up to 22 Tesla are available. This new class of high field magnet weighs under 200 kg and is suitable for general laboratory installation. In addition, extremely compact, high field, split pair magnets with open access are now operating at the elevated temperature of T = 4.2 K. Beyond conventional wet magnet technology, there is a growing trend to utilize cryogen free technology. Cryogen free magnets do not require liquid Helium baths and, with the addition of active shielding, both the experimental sample access and siting availability is improved. The influence of enabling technologies required to realize the above practical applications for high field, superconducting magnet systems is described.

Ginzburg-Landau theory of noncentrosymmetric superconductors

The data of temperature dependent superfluid density $n_s(T)$ in Li$_2$Pd$_3$B and Li$_2$Pt$_3$B [Yuan {\it et al.}, \phrl97, 017006 (2006)] show that a sudden change of the slope of $n_s (T)$ occur at slightly lower than the critical temperature. Motivated by this observation, we microscopically derive the Ginzburg-Landau (GL) equations for noncentrosymmetric superconductors with Rashba type spin orbit interaction. Cooper pairing is assumed to occur between electrons only in the same spin split band and pair scattering is allowed to occur between two spin split bands. The GL theory of such a system predicts two transition temperatures, the higher of which is the conventional critical temperature $T_c$ while the lower one $T^*$ corresponds to the cross-over from a mixed singlet-triplet phase at lower temperatures to only spin-singlet or spin-triplet (depending on the sign of the interband scattering potential) phase at higher temperatures. As a consequence, $n_s (T)$ shows a kink at this cross-over temperature. We attribute the temperature at which sudden change of slope occurs in the observed $n_s (T)$ to the temperature $T^*$. This may also be associated with the observed kink in the penetration depth data of CePt$_3$Si. We have also estimated critical field near critical temperature.

Cohomological reduction by split pairs

A new method is developed to compare cohomology in module categories of different rings. This method does in general not produce isomorphisms, but surjective (or injective) maps between extension groups of modules over the two rings involved. Applications of this method are given to abstract problems—we recover and extend results on the strong no loops conjecture—and to algebras naturally coming up in invariant theory—we relate the cohomology of Brauer algebras with that of various symmetric groups.

On local lifts from G2(ℝ) to Sp6(ℝ) and F4(ℝ)

Let G2(ℝ) × Sp6(ℝ) and G2(ℝ) × F4(ℝ) be split dual pairs in split E7(ℝ) and E8(ℝ), respectively. It is known that the exceptional correspondences for these dual pairs are functorial on the level of infinitesimal characters. In this paper we show that these dual pair correspondences are functorial for the minimal K-types of principal series representations.

Travelling circular waves in axisymmetric rotating convection

Rayleigh–Bénard convection in a finite rotating cylinder of moderate aspect ratio (radius four times the depth) is investigated numerically for a fluid of Prandtl number equal to 7 (corresponding essentially to water). We consider the effects of rotation from both the Coriolis force and the centrifugal force and find that the centrifugal force plays a significant dynamic role. In this initial study, we restrict the computations to the axisymmetric subspace in which the convection patterns near onset consist of steady concentric circular cells, the so-called target patterns, which have been studied and observed experimentally under different conditions by a number of investigators. As the convection is driven far enough beyond onset, the steady cellular patterns give way to time-periodic states in which the target patterns travel radially inward. We have identified two such travelling modes, primarily distinguished by one having alternating warm and cold plumes forming at the cylinder sidewall and then propagating radially inward to quench alternately cold and warm plumes on the axis. The other mode always has a cold plume descending on the sidewall and the adjacent warm plume periodically splits into two, with the innermost of the split pair travelling radially inward. The first of these modes is found when the centrifugal force is weak and the second for stronger centrifugal force. The large-scale meridional circulation driven by the centrifugal buoyancy is seen to favour having a cold plume descending on the sidewall, accounting for the switch to the second travelling mode.

Compact multiple output linear V to I converters using split differential pairs and applications in allpass OTAs

The compact implementation of multiple output linear V to I converters using split differential pairs is discussed. A first-order allpass/lowpass/highpass OTA is discussed as a simple application example. Experimental results of a test chip are reported that validate the proposed circuits.

Design & Testing of a Repetitively Pulsed Magnet for Neutron Scattering

The National High Magnetic Field Laboratory in Tallahassee, Florida, USA has designed, built and tested a high field, split pair, Repetitively Pulsed Magnet (RPM) suitable for neutron scattering experiments. RPM magnets have the advantage of lower average power and lower construction costs than DC magnets. The NHMFL RPM program intends to build magnets with higher field and larger scattering space than those available elsewhere. Details of design and testing of the first prototype are presented

Dispersive measurements of superconducting qubit coherence with a fast latching readout

The "quantronium" is a superconducting qubit consisting of a split Cooper pair box in which a large tunnel junction is inserted. This circuit has a special bias point where the Larmor frequency is, to first order, insensitive to fluctuations in the bias parameters -- the charge of the box island and the phase of the large junction. At this optimal working point, the state of the qubit can be determined by dispersive measurements that probe the second derivative of the state energy with respect to these bias parameters. We use the quantronium phase degree of freedom to perform a non-linear, dispersive measurement of its inductive response using bifurcation amplification. This novel readout projects the state of the qubit in a few nanoseconds, and its latching property allows us to record the resulting information in a few hundred nanoseconds. We have measured, using this technique, Rabi oscillations and Ramsey fringes with an improved signal to noise ratio and contrast. The speed of this new readout scheme also opens the door for a new class of experiments which would characterize the relaxation processes associated with the measurement protocol.

Direct Observation of Josephson Capacitance

The effective capacitance has been measured in the split Cooper-pair box (CPB) over its phase-gate bias plane. Our low-frequency reactive measurement scheme allows us to probe purely the capacitive susceptibility due to the CPB band structure. The data are quantitatively explained using parameters determined independently by spectroscopic means. In addition, we show in practice that the method offers an efficient way to do nondemolition readout of the CPB quantum state.

Spin-current noise and Bell inequalities in a realistic superconductor-quantum dot entangler

Charge and spin current correlations are analyzed in a source of spin-entangled electrons built from a superconductor and two quantum dots in parallel. In addition to the ideal (crossed Andreev) channel, parasitic channels (direct Andreev and cotunneling) and spin flip processes are fully described in a density matrix framework. The way they reduce both the efficiency and the fidelity of the entangler is quantitatively described by analyzing the zero-frequency noise correlations of charge current as well as spin current in the two output branches. Spin current noise is characterized by a spin Fano factor, equal to 0 (total current noise) and -1 (crossed correlations) for an ideal entangler. The violation of the Bell inequalities, as a test of non-locality (entanglement) of split pairs, is formulated in terms of the correlations of electron charge and spin numbers counted in a specific time window $\tau$. The efficiency of the test is analyzed, comparing $\tau$ to the various time scales in the entangler operation.

Electronic Structure, Spectra, and Magnetic Circular Dichroism of Cyclohexa‐, Cyclohepta‐, and Cyclooctapyrrole

Three recently obtained expanded porphyrins represent nice examples of compounds for which the electronic and spectral properties can be predicted from symmetry considerations alone. Perimeter-model-based theoretical analysis of the electronic structure of doubly protonated cyclo[6], cyclo[7], and cyclo[8]pyrrole leads to the anticipation of qualitatively the same electronic absorption and magnetic circular dichroism patterns for all three compounds. These predictions are fully confirmed by experiments, as well as DFT and INDO/S calculations. Due to a characteristic pattern of frontier molecular orbitals, a degenerate HOMO and a strongly split LUMO pair, the three cyclopyrroles show comparable absorption intensity in the Q and Soret regions. Magnetic circular dichroism spectra reveal both A and B Faraday terms, of which the signs and magnitudes are in remarkably good agreement with theoretical expectations. The values of the magnetic moments of the two lowest degenerate excited states have also been obtained.

Dynamical hydrogen atom tunneling in dichlorotropolone: A combined quantum, semiclassical, and classical study

Based on the Cartesian Reaction Surface framework we construct a four-dimensional potential for the tropolone derivative 3,7-dichlorotropolone, a molecule with an intramolecular O-H...O hydrogen bond. The reduced configuration space involves the in-plane hydrogen atom coordinates, a symmetric O-O vibrational mode, and an antisymmetric mode related to deformations of the seven-membered ring. The system is characterized in terms of quantum mechanical computations of the low-lying eigenstates as well as a classical and semiclassical analysis of spectra obtained via Fourier transforming autocorrelation functions. For the semiclassical analysis we utilize the amplitude-free correlation function method [K. Hotta and K. Takatsuka, J. Phys. A 36, 4785 (2003)]. Our results demonstrate substantial anharmonic couplings leading to highly correlated wave functions even at moderate energies. Furthermore, the importance of dynamical tunneling in tropolone is suggested since many low-lying states--including the ground state--lie above the classical saddle point but nevertheless appear as split pairs.

ABELIAN EXACT SUBCATEGORIES CLOSED UNDER PREDECESSORS#†

ABSTRACT In the category of finitely generated modules over an artinian ring, we classify all the abelian exact subcategories closed under predecessors or, equivalently, all the split torsion pairs with torsion-free class closed under quotients. In the context of artin algebras, the result is then applied to the left part of the module category and to local extensions of hereditary algebras.

Calculated properties of point defects in Be-doped GaN

The properties of several point defects in hexagonal gallium nitride that can compensate beryllium shallow acceptors $({\mathrm{Be}}_{\mathrm{Ga}})$ are calculated using the AIMPRO method based on local density functional theory. ${\mathrm{Be}}_{\mathrm{Ga}}$ itself is predicted to have local vibrational modes (LVM's) very similar to magnesium acceptors. The highest frequency is about $663{\mathrm{cm}}^{\ensuremath{-}1}.$ Consistent with other recent studies, we find that interstitial beryllium double donors and single-donor beryllium split interstitial pairs at gallium sites are very likely causes of compensation. The calculations predict that the split interstitial pairs possess three main LVM's at about 1041, 789, and $738{\mathrm{cm}}^{\ensuremath{-}1}.$ Of these, the highest is very close to the experimental observation in Be-doped GaN. Although an oxygen donor at the nearest-neighboring site to a beryllium acceptor $({\mathrm{Be}}_{\mathrm{Ga}}\ensuremath{-}{\mathrm{O}}_{\mathrm{N}})$ is also a prime suspect among defects that are possibly responsible for compensation, its highest frequency is calculated to be about $699{\mathrm{cm}}^{\ensuremath{-}1}$ and hence is not related in any way to the observed center. Another mode for this defect is estimated to be about $523{\mathrm{cm}}^{\ensuremath{-}1}$ and is localized on the ${\mathrm{O}}_{\mathrm{N}}$ atom. These two vibrations of ${\mathrm{Be}}_{\mathrm{Ga}}\ensuremath{-}{\mathrm{O}}_{\mathrm{N}}$ are thus equivalent to those for the isolated substitutional centers perturbed by the presence of their impurity partners.

Liquid-He-free 10-T superconducting magnet for neutron scattering

A new type of superconducting magnet, which is directly cooled by two 4-K GM cryocoolers (i.e. liquid-He-free), has been developed for neutron-scattering experiments. The magnet consists of a split pair of a (Nb, Ti)3Sn inner coil and a NbTi outer coil. The gap between the coils is 29 mm, and the upper and lower coils are supported by three rings made of Al alloy (4.5, 7.5, and 8 mm in thickness) and a plate of Al alloy (42.5° in angle). The total thickness of the Al alloy in the neutron path is 52 mm, and the transmission of the beam is about 60% for neutrons with 20 meV. The room-temperature bore is 51 mm in diameter, and in this bore one of the sample-cooling systems (4-K cryocooler or liquid-He-free dilution refrigerator) is inserted. The maximum field of 10 T is very stably obtained. Some results on the magnetism of strongly correlated electron systems obtained with this cryomagnet are presented.