Isolation and characterization of sixty sequences of cot-1 DNA from the Asiatic black bear, Ursus thibetanus

The Asiatic black bear (Ursus thibetanus) is a class II protected species in China whose genome is not well characterized. All mammalian genomes have a high proportion of repetitive sequences; thus, studying the repetitive sequences of the Asiatic black bear can provide new insight into the organization of its genome. It is well known that cot-1 DNA is enriched for repetitive DNA elements with high and moderately high copy numbers within the genome. In this small-scale study, cot-1 DNA from U. thibetanus was first isolated and characterized using DNA reassociation kinetics, then a Southern blotting probe was used to indicate the presence of polymorphic repetitive DNA families in this species. Analysis of homologous sequences by online database searches revealed that the obtained fragments contained satellite sequences, mitochondrial DNA, retrotransposons, DNA transposons, and unclassified fragments whose deduced amino acid sequences has significant relationships to known proteins. The data produced by this study may lead to more research into repetitive DNAs.Key words: Asiatic black bear, cot-1 DNA, repetitive elements, southern blottin

Phenomenological analysis of the quasi-two-body B→D(R→)KπB \to D (R\to) K \pi decays in PQCD Approach

The quasi-two-body $B \to D (R\to) K \pi$ decays are calculated in PQCD approach based on the $k_T$ factorization by introducing the wave functions of $K\pi$ pair associated with the resonances $K^*(892)$, $K_0^*(1430)$ and $K_2^*(1430)$. The results show that most branching fractions are at the order of $10^{-7}$ or even smaller. However, for $B^0\to D^0(K^*\to)K\pi$ decays enhanced by the CKM element $V_{cs}$, their branching fractions are at the order of $10^{-6}$, which are measurable in the current ongoing experiments. Based on the narrow-width-approximation we also extract the branching fractions of the corresponding two-body $B \to D K^*$ decays and the results are in good agreement with previous predictions. Because these decays are only governed by the tree operators, there are no $CP$ asymmetries in these decays in the standard model.Comment: 15 pages, 1 figur

On the measurement of the Hubble constant in a local low-density universe

Astrophysical observations indicate that the ``Local Universe" has a relatively lower matter density ($\Omega_0$) than the predictions of the standard inflation cosmology and the large-scale motions of galaxies which provide a mean mass density to be very close to unity. In such a local underdense region the Hubble expansion may not be representative of the global behaviour. Utilizing an underdense sphere embedded in a flat universe as the model of our ``Local Universe", we show that the local Hubble constant would be 1.2 -- 1.4 times larger than the global value on scale of $\sim80$ Mpc, depending on the variation of $\Omega_0$. This may account for the recent measurements of the unpleasantly large Hubble constant of $\sim$80 km/s/Mpc using the Cepheid variables in the Virgo cluster and the relative distance between Virgo and Coma cluster and removes the resulted apparent paradox of the age of our universe.Comment: 9 pages, Latex file, 3 figures available by reques

Broadband enhancement of light harvesting in luminescent solar concentrator

Luminescent solar concentrator (LSC) can absorb large-area incident sunlight, then emit luminescence with high quantum efficiency, which finally be collected by a small photovoltaic (PV) system. The light-harvesting area of the PV system is much smaller than that of the LSC system, potentially improving the efficiency and reducing the cost of solar cells. Here, based on Fermi-golden rule, we present a theoretical description of the luminescent process in nanoscale LSCs where the conventional ray-optics model is no longer applicable. As an example calculated with this new model, we demonstrate that a slot waveguide consisting of a nanometer-sized low-index slot region sandwiched by two high-index regions provides a broadband enhancement of light harvesting by the luminescent centers in the slot region. This is because the slot waveguide can (1) greatly enhance the spontaneous emission due to the Purcell effect, (2) dramatically increase the effective absorption cross-section of luminescent centers, and (3) strongly improve the quantum efficiency of luminescent centers. It is found that about 80% solar photons can be ultimately converted to waveguide-coupled luminescent photons even for a low luminescent quantum efficiency of 0.5. This LSC is potential to construct a tandem structure which can absorb nearly full-spectrum solar photons, and also may be of special interest for building integrated nano-PV applications

Analysis of CKM-Favored Quasi-Two-Body B→D(R→)KπB \to D (R\to) K \pi Decays in PQCD Approach

LHCb Collaboration studied the resonant structure of $B_s\to \overline{D}^0K^-\pi^+$ decays using the Dalitz plot analysis technique, based on a data sample corresponding to an integrated luminosity of $3.0{\rm fb}^{-1}$ of $pp$ collision. The $K^-\pi^+$ components have been analyzed in the amplitude model, where the decay amplitude is modeled to be the resonant contributions with respect to the intermediate resonances $K^*(892)$, $K_0^*(1430)$ and $K_2^*(1430)$. Motivated by the experimental results, we investigate the color-favored quasi-two-body $B \to \overline{D}^0K\pi$ decays in the framework of the perturbative QCD (PQCD) approach. We calculate the the branching fractions by introducing the appropriate wave functions of $K\pi$ pair. Our results are in agreement well the available data, and others can be tested in LHCb and Belle-II experiments. Using the narrow-width-approximation, we also extract the branching fractions of the corresponding two-body $B\to \overline D R$ decays, which agree to the previous theoretical calculations and the experimental data within the errors. There are no $CP$ asymmetries in these decays in the standard model, because these decays are all governed by only the tree operators.Comment: 18 pages, 1 figure

Synthesis of Consequent Pole Vernier Permanent Magnet Machine Based on Oscillating Magnetic Potential Difference Model

In recent years, consequent pole vernier permanent magnet machine (CPVPMM) has been found higher torque capability and less magnet usage compared to the surface-mounted counterpart i.e. SVPMM, thus attracting extensive interests. Meanwhile, the theoretical basis of CPVPMM is not well established because of its unconventional PM arrangement. Due to the simplified dual-salient permeance model widely adopted in CPVPMM, the misinterpretation in time-space distribution of magnetizing magnetomotive force (MMF) and air-gap permeance leads to deviated sizing equations, which hinders the development of CPVPMM. This paper proposes a new analytical model, i.e. the magnetic potential difference between stator core and rotor surface, based on the modified dual-salient permeance and the resultant improved MMF. Via the proposed model, a new analytical derivation featuring precise calculation of air-gap flux density is obtained to clarify the working mechanism of CPVPMM and give helpful design hints to fulfill high torque density. For the first time, it is identified the phenomenon of potential difference oscillation and additional harmonic exist in both CPVPMM and SVPMM. The influence of potential difference oscillation on working flux density is quantitatively analyzed, which reveals the operation principle of CPVPMM, and also unveils the underlying torque improvement mechanism over SVPMM, which gives new insight on enhancing torque of vernier machines. Finally, the analytical and FEA results are validated by experiments

rac-(S)-2-(1H-Imidazol-1-yl)-3-methyl­butan-1-ol

In the crystal structure of the title compound, C8H14N2O, inter­molecular O—H⋯N hydrogen bonds link mol­ecules related by translation along the a axis into chains. Weak inter­molecular C—H⋯O hydrogen bonds and C—H⋯π inter­actions enhance the crystal packing stability

(1E,4E)-1-(Thio­phen-2-yl)-5-(2,6,6-trimethyl­cyclo­hex-1-en-1-yl)penta-1,4-dien-3-one

In the title curcumin–ionone derivative, C18H22OS, the dihedral angle between the thia­zole ring and the mean plane through the cyclo­hexene ring is 5.16 (10)°. The mol­ecule has an E conformation for each of the olefinic bonds

High remission and low relapse with prolonged intensive DMARD therapy in rheumatoid arthritis (PRINT): A multicenter randomized clinical trial

Objectives: To determine whether prolonged intensive disease-modifying antirheumatic drug (DMARD) treatment (PRINT) leads to high remission and low relapse rates in patients with severe rheumatoid arthritis (RA). Methods: In this multicenter, randomized and parallel treatment trial, 346 patients with active RA (disease activity score (28 joints) [DAS28] (erythrocyte sedimentation rate [ESR]) > 5.1) were enrolled from 9 centers. In phase 1, patients received intensive treatment with methotrexate, leflunomide, and hydroxychloroquine, up to 36 weeks, until remission (DAS28 ≤ 2.6) or a low disease activity (2.6 < DAS28 ≤ 3.2) was achieved. In phase 2, patients achieving remission or low disease activity were followed up with randomization to 1 of 2 step-down protocols: leflunomide plus hydroxychloroquine combination or leflunomide monotherapy. The primary endpoints were good European League Against Rheumatism (EULAR) response (DAS28 (ESR) < 3.2 and a decrease of DAS28 by at least 1.2) during the intensive treatment and the disease state retention rate during step-down maintenance treatment. Predictors of a good EULAR response in the intensive treatment period and disease flare in the maintenance period were sought. Results: A good EULAR response was achieved in 18.7%, 36.9%, and 54.1% of patients at 12, 24, and 36 weeks, respectively. By 36 weeks, 75.4% of patients achieved good and moderate EULAR responses. Compared with those achieving low disease activity and a high health assessment questionnaire (HAQ > 0.5), patients achieving remission (DAS28 ≤ 2.6) and low HAQ (≤ 0.5) had a significantly higher retention rate when tapering the DMARDs treatment (P = 0.046 and P = 0.01, respectively). There was no advantage on tapering to combination rather than monotherapy. Conclusions: Remission was achieved in a proportion of patients with RA receiving prolonged intensive DMARD therapy. Low disease activity at the start of disease taper leads to less subsequent flares. Leflunomide is a good maintenance treatment as single treatment