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Now showing items 1 - 16 of 361

  • Landau equation and QCD sum rules for the tetraquark molecular states

    Wang, Zhi-Gang  

    The quarks and gluons are confined objects; they cannot be put on the mass shell. It is questionable to apply the Landau equation to study the Feynman diagrams in the QCD sum rules. Furthermore, we carry out the operator product expansion in the deep Euclidean region p(2) -> -infinity, where the Landau singularities cannot exist. The Landau equation servers as a kinematical equation in the momentum space and is independent on the factorizable and nonfactorizable properties of the Feynman diagrams in the color space. The meson-meson scattering state and tetraquark molecular state both have four valence quarks, which form two color-neutral clusters; we cannot distinguish the contributions based on the two color-neutral clusters in the factorizable Feynman diagrams. Lucha et al. assert that the contributions at the order O(alpha(k)(s)) with k <=3D 1 in the operator product expansion, which are factorizable in the color space, are exactly canceled out by the meson-meson scattering states at the hadron side, and the tetraquark molecular states begin to receive contributions at the order O(alpha(2)(s)). Such an assertion is questionable, we refute the assertion in details, and choose an axial-vector current and a tensor current to examine the outcome of the assertion. After a detailed analysis, we observe that the meson-meson scattering states cannot saturate the QCD sum rules, while the tetraquark molecular states can saturate the QCD sum rules. The Landau equation is of no use to study the Feynman diagrams in the QCD sum rules for the tetraquark molecular states; the tetraquark molecular states begin to receive contributions at the order O(alpha(0)(s)/alpha(1)(s)) rather than at the order O(alpha(2)(s)).
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  • Analysis of the X(3842) as a D-wave charmonium meson

    Yu, Guo-Liang   Wang, Zhi-Gang  

    In this paper, we assign the newly reported state X(3842) to be a D-wave (c) over barc meson, and study its mass and decay constant with QCD sum rules by considering the contributions of vacuum condensates up to dimension-6 in the operator product expansion. The predicted mass M-X(3842) =3D (3.844(-0.0823)(+0.0675) +/- 0.020) GeV is in agreement with the experimental data M-X(3842) =3D (3842.71 +/- 0.16 +/- 0.12) MeV from the LHCb collaboration. This result supports assigning X(3842) as the 1(3)D(3) charmonium meson. In this case, its predicted strong decay width with the P-3(0) decay model is compatible with the experimental data.
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  • A new cinnamic acid glycoside from roots of Heracleum dissectum

    Wang, Zhi-Gang   Mi, Jie   Wang, Xin-Rui   Huo, Ya-Yu   Peng, Ya-Jie   Zhang, Hai-Min   Gao, Yang   Zhang, Hai-Long  

    From the roots of Heracleum dissectum Lebb., one new cinnamic acid glycoside derivative named dissectumoside (1), together with eight known compounds including three phenolics, three phenolic glycosides and two phenylpropanoic glycoside were isolated using various chromatographic methods. Among them compound 2-9 was isolated from the plant for the first time. Their structures were elucidated and identified on the basis of their physicochemical properties and by extensive analyses of NMR spectroscopy and high-resolution mass spectrometry. The results of triglyceride accumulation screening in 3T3-L1 cells showed that compounds 1, 5 and 9 exhibited significantly accelerating activities of adipogenesis in adipocytes.
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  • Effect of vanadium and nickel on iron-rich ash fusion characteristics

    Wang, Zhi-Gang   Kong, Ling-Xue   Bai, Jin   Li, Huai-Zhu   He, Chong   Yan, Ting-Gui   Guo, Zhen-Xing   Bai, Zong-Qing   Li, Wen  

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  • Strong coupling constants and radiative decays of the heavy tensor mesons

    Yu, Guo-Liang   Wang, Zhi-Gang   Li, Zhen-Yu  

    In this article, we analyze tensor-vector-pseudoscalar(TVP) type of vertices D2*+D+rho\D2*0D0 rho\D2*+D+omega\D2*0D0 omega B2*+B+rho\B2*0B0 rho B2*+B+omega B2*0B0 omega Bs2*Bs phi Ds2*Ds phi in the frame work of three point QCD sum rules(QCDSR). According to these analysis, we calculate their strong form factors which are used to fit into analytical functions of . Then, we obtain the strong coupling constants by extrapolating these strong form factors into deep time-like regions. As an application of this work, the coupling constants for radiative decays of these heavy tensor mesons are also calculated at the point of Q(2). With these coupling constants, we finally obtain the radiative decay widths of these tensor mesons.
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  • Analysis of the triply-charmed pentaquark states with QCD sum rules

    Wang, Zhi-Gang  

    In this article, we construct the scalar-diquark-scalar-diquark-antiquark type current to study the ground state triply-charmed pentaquark states with the QCD sum rules. We separate the contributions of the negative-parity and positive-parity triply-charmed pentaquark states explicitly, and take the energy scale formula mu =3D root M-P(2) - (3M(c))(2) to determine the optimal energy scales of the QCD spectral densities. The predicted pentaquark masses can be confronted to the experimental data in the future.
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  • Possible pentaquark candidates: new excited Omega(c) states

    Wang, Zhi-Gang   Zhang, Jun-Xia  

    In this article, we study the axialvector-diquark- scalar-diquark-antiquark type charmed pentaquark states with J(P) =3D 3/2(+/-) with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension 13 in a consistent way. In calculations, we separate the contributions of the negative parity and positive parity pentaquark states unambiguously, and choose three sets input parameters to study the masses and pole residues of the charmed pentaquark states uuuc (u) over bar and sssc (s) over bar in details. Then we estimate the masses of the charmed pentaquark states ssuc (u) over bar, susc (u) over bar, ssdc (d) over bar and sdsc (d) over bar with J(P) =3D 3/2(-) to be 3.15 +/- 0.13 GeV according to the SU (3) breaking effects, which is compatible with the Omega(c)(3050), Omega(c)(3066), Omega(c)(3090), Omega(c)(3119).
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  • Slowing down of alpha particles in ICF DT plasmas

    He, Bin   Wang, Zhi-Gang   Wang, Jian-Guo  

    With the effects of the projectile recoil and plasma polarization considered, the slowing down of 3.54MeV alpha particles is studied in inertial confinement fusion DT plasmas within the plasma density range from 10(24) to 10(26) cm(-3) and the temperature range from 100 eV to 200 keV. It includes the rate of the energy change and range of the projectile, and the partition fraction of its energy deposition to the deuteron and triton. The comparison with other models is made and the reason for their difference is explored. It is found that the plasmas will not be heated by the alpha particle in its slowing down the process once the projectile energy becomes close to or less than the temperature of the electron or the deuteron and triton in the plasmas. This leads to less energy deposition to the deuteron and triton than that if the recoil of the projectile is neglected when the temperature is close to or higher than 100 keV. Our model is found to be able to provide relevant, reliable data in the large range of the density and temperature mentioned above, even if the density is around 10 26 cm(-3) while the deuteron and triton temperature is below 500 eV. Meanwhile, the two important models [Phys. Rev. 126, 1 (1962) and Phys. Rev. E 86, 016406 (2012)] are found not to work in this case. Some unreliable data are found in the last model, which include the range of alpha particles and the electron-ion energy partition fraction when the electron is much hotter than the deuteron and triton in the plasmas. Published by AIP Publishing.
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  • Lowest vector tetraquark states: Y(4260/4220) or Z(c)(4100)

    Wang, Zhi-Gang  

    In this article, we take the Y (4260/4220) as the vector tetraquark state with J(PC) =3D 1(--), and construct the C gamma 5 circle times (partial derivative) over left right arrow (mu) circle times gamma 5C type diquark-antidiquark current to study its mass and pole residue with the QCD sum rules in details by taking into account the vacuum condensates up to dimension 10 in a consistent way. The predicted mass MY =3D 4.24 +/- 0.10 GeV is in excellent agreement with experimental data and supports assigning the Y (4260/4220) to be the C gamma 5 circle times (partial derivative) over left right arrow (mu) circle times gamma 5C type vector tetraquark state, and disfavors assigning the Z(c)(4100) to be the C gamma 5 circle times (partial derivative) over left right arrow (mu) circle times gamma 5C type vector tetraquark state. It is the first time that the QCD sum rules have reproduced the mass of the Y (4260/4220) as a vector tetraquark state.
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  • Single-Virus Tracking:From Imaging Methodologies to Virological Applications

    Liu, Shu-Lin   Wang, Zhi-Gang   Xie, Hai-Yan   Liu, An-An   Lamb, Don C.   Pang, Dai-Wen  

    Uncovering the mechanisms of virus infection and assembly is crucial for preventing the spread of viruses and treating viral disease. The technique of single-virus tracking (SVT), also known as single-virus tracing, allows one to follow individual viruses at different parts of their life cycle and thereby provides dynamic insights into fundamental processes of viruses occurring in live cells. SVT is typically based on fluorescence imaging and reveals insights into previously unreported infection mechanisms. In this review article, we provide the readers a broad overview of the SVT technique. We first summarize recent advances in SVT, from the choice of fluorescent labels and labeling strategies to imaging implementation and analytical methodologies. We then describe representative applications in detail to elucidate how SVT serves as a valuable tool in virological research. Finally, we present our perspectives regarding the future possibilities and challenges of SVT.
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  • A New Anti-Inflammatory Alkaloid from Roots of Heracleum dissectum

    Zhang, Hai-Long   Wu, Xin-Yuan   Mi, Jie   Peng, Ya-Jie   Wang, Zhi-Gang   Liu, Ying   Wu, Xiu-Li   Gao, Yang  

    Using various chromatographic methods, a new piperidinone alkaloid, (3S)-3-{4-[(1E)-3-hydroxyprop-1-en-1-yl]-2-methoxyphenoxy}piperidin-2-one (1), together with 10 known compounds, bergapten (2), xanthotoxol (3), isopimpinellin (4), isobergapten (5), heratomol-6-O-beta-d-glucopyranoside (6), scopoletin (7), apterin (8), 3-methoxy-4-beta-d-glucopyranosyloxypropiophenone, (praeroside; 9), tachioside (10) and coniferin (11), were isolated from roots of Heracleum dissectum Ledeb. Their structures were elucidated on the basis of physicochemical properties and the detailed interpretation of various spectroscopic data. All the isolated compounds were screened for anti-inflammatory activity in vitro. As the results, compound 1 and 8 showed significantly inhibitory activity on nitric oxide production in RAW264.7 cells.
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  • Some properties of certain extended fractional differintegral operator

    Wang, Zhi-Gang   Shi, Lei  

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  • On a subclass of starlike functions associated with a vertical strip domain

    Sun, Yong   Wang, Zhi-Gang   Rasila, Antti   Sokol, Janusz  

    In this paper, we consider a subclass of starlike functions associated with a vertical strip domain. We obtain several results concerned with integral representations, convolutions, and coefficient inequalities for functions belonging to this class. Furthermore, we consider radius problems and inclusion relations involving certain classes of strongly starlike functions, parabolic starlike functions, and other types of starlike functions. The results are essential improvements of the corresponding results obtained by Kargar et al., and the derivations are similar to those used earlier by Sun et al. and Kwon et al.
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  • Analysis of the scalar doubly charmed hexaquark state with QCD sum rules

    Wang, Zhi-Gang  

    In this article, we study the scalar-diquark-scalar-diquark-scalar-diquark type hexaquark state with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension 16. We obtain a lowest hexaquarkmass of 6.60(-0.09)(+0.12) GeV, which can be confronted with the experimental data in the future.
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  • Strong decays of heavy tensor mesons in QCD sum rules

    Li, Zhen-Yu   Wang, Zhi-Gang   Yu, Guo-Liang  

    In this paper, the tensor-vector-pseudoscalar (TVP) type of vertices are analyzed with the QCD sum rules (QCDSR) and the local-QCD sum rules (SR) in the leading-order approximation and the hadronic coupling constants G(D2*D*pi), G(Ds2*D*K), G(B2*B*pi) and G(Bs2*B* K) together with the corresponding decay widths are then calculated. The results indicate that QCDSR as well as the local-QCDSR give a consistent description. The calculated strong decay widths and decay width ratios are compared with the available experimental and other theoretical values. Finally, the total widths Gamma(D-2*(2460)(0)), Gamma(D-s2*(2573)), Gamma(B-s2*(5747)(0)) and Gamma(B-s2*(5840)(0)) are discussed in detail. The results show that these total widths are underestimated, especially for the tensor B-2* and B-s2* mesons where the obtained predictions are almost a factor of 2 lower than measured decay widths.
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  • Role of thymosin beta 4 in hair growth

    Gao, Xiao-yu   Hou, Fang   Zhang, Zhi-peng   Nuo, Ming-tu   Liang, Hao   Cang, Ming   Wang, Zhi-gang   Wang, Xin   Xu, Teng   Yan, Le-yan   Guo, Xu-dong   Liu, Dong-jun  

    Although thymosin beta 4 (T beta 4) is known to play a role in hair growth, its mechanism of action is unclear. We examined the levels of key genes in a T beta 4 epidermal-specific over-expressing mouse model and T beta 4 global knockout mouse model to explore how T beta 4 affects hair growth. By depilation and histological examination of the skin, we confirmed the effect of T beta 4 on hair growth, the number of hair shafts and hair follicle (HF) structure. The mRNA and protein expression of several genes involved in hair growth were detected by real-time PCR and western blotting, respectively. Changes in the expression of beta-catenin and Lef-1, the two key molecules in the Wnt signaling pathway, were similar to the changes observed in T beta 4 expression. We also found that compared to the control mice, the mRNA and protein expression of MMP-2 and VEGF were increased in the T beta 4 over-expressing mice, while the level of E-cadherin (E-cad) remained the same. Further, in the T beta 4 global knockout mice, the mRNA and protein levels of MMP-2 and VEGF decreased dramatically and the level of E-cad was stable. Based on the above results, we believe that T beta 4 may regulate the levels of VEGF and MMP-2 via the Wnt/beta-catenin/Lef-1 signaling pathway to influence the growth of blood vessels around HFs and to activate cell migration. T beta 4 may have potential for the treatment of hair growth problems in adults, and its effects should be further confirmed in future studies.
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