Inner core composition paradox revealed by sound velocities of Fe and Fe-Si alloy

Knowledge of the sound velocity of core materials is essential to explain the observed anomalously low shear wave velocity (VS) and high Poisson's ratio (σ) in the solid inner core. To date, neither VS nor σ of Fe and Fe-Si alloy have been measured under core conditions. Here, we present VS and σ derived from direct measurements of the compressional wave velocity, bulk sound velocity, and density of Fe and Fe-8.6 wt%Si up to ~230 GPa and ~5400 K. The new data show that neither the effect of temperature nor incorporation of Si would be sufficient to explain the observed low VS and high σ of the inner core. A possible solution would add carbon (C) into the solid inner core that could further decrease VS and increase σ. However, the physical property-based Fe-Si-C core models seemingly conflict with the partitioning behavior of Si and C between liquid and solid Fe.

From chaos to a new norm: The Birmingham experience of restructuring the largest plastics department in the UK in response to the COVID-19 pandemic

The coronavirus disease 2019 (COVID-19) pandemic presented unprecedented challenges for healthcare systems worldwide. The Queen Elizabeth Hospital, Birmingham, has one of the largest burns, hands and plastics department in the UK, totalling 83 doctors. Our response to the COVID-19 response was uniquely far reaching, with our department being given responsibility of an entire 36 bed medical COVID-19 ward in addition to our commitment to specialty-specific work, and saw half of our work force re-deployed to Intensive Treatment Unit (ITU). Our aim was to exploit the high calibre of doctors found in plastic surgery, and to demonstrate, we were able to support the COVID-19 effort beyond our normal scope of practice.

In order to achieve this aim, the department underwent significant structural and leadership changes. Factors considered included: rota and shift pattern changes to implement depth and resilience to sudden fluctuations in staffing levels; a preparatory phase for focussed upskilling and relevant training packages to be delivered; managing the COVID-19 ward cover and ITU deployment; adjustments to our front of house and elective specialty-specific service, including developing alternative and streamlined patient pathways; mitigating the effects on plastic surgical training during the pandemic; the importance of communications for patient care and physician wellbeing; and leadership techniques and styles we considered important.

By sharing our experience during this pandemic, we hope to reflect on and share lessons learned, as well as to demonstrate that it is possible to rapidly mobilise and retrain plastic surgeons at all levels to contribute safely and productively beyond a specialty-specific scope of care.

Evidence of a Resonant Structure in the e^{+}e^{-}→π^{+}D^{0}D^{*-} Cross Section between 4.05 and 4.60 GeV

The cross section of the process e^{+}e^{-}→π^{+}D^{0}D^{*-} for center-of-mass energies from 4.05 to 4.60 GeV is measured precisely using data samples collected with the BESIII detector operating at the BEPCII storage ring. Two enhancements are clearly visible in the cross section around 4.23 and 4.40 GeV. Using several models to describe the dressed cross section yields stable parameters for the first enhancement, which has a mass of 4228.6±4.1±6.3  MeV/c^{2} and a width of 77.0±6.8±6.3  MeV, where the first uncertainties are statistical and the second ones are systematic. Our resonant mass is consistent with previous observations of the Y(4220) state and the theoretical prediction of a DD[over ¯]_{1}(2420) molecule. This result is the first observation of Y(4220) associated with an open-charm final state. Fits with three resonance functions with additional Y(4260), Y(4320), Y(4360), ψ(4415), or a new resonance do not show significant contributions from either of these resonances. The second enhancement is not from a single known resonance. It could contain contributions from ψ(4415) and other resonances, and a detailed amplitude analysis is required to better understand this enhancement.

Measurement of the Absolute Branching Fraction of the Inclusive Semileptonic Λ_{c}^{+} Decay

Using a data sample of e^{+}e^{-} collisions corresponding to an integrated luminosity of 567  pb^{-1} collected at a center-of-mass energy of sqrt[s]=4.6  GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive semileptonic Λ_{c}^{+} decay with a double-tag method. We obtain B(Λ_{c}^{+}→Xe^{+}ν_{e})=(3.95±0.34±0.09)%, where the first uncertainty is statistical and the second systematic. Using the known Λ_{c}^{+} lifetime and the charge-averaged semileptonic decay width of nonstrange charmed mesons (D^{0} and D^{+}), we obtain the ratio of the inclusive semileptonic decay widths Γ(Λ_{c}^{+}→Xe^{+}ν_{e})/Γ[over ¯](D→Xe^{+}ν_{e})=1.26±0.12.

Measurement of the Branching Fraction For the Semileptonic Decay D^{0(+)}→π^{-(0)}μ^{+}ν_{μ} and Test of Lepton Flavor Universality

Using a data sample corresponding to an integrated luminosity of 2.93  fb^{-1} taken at a center-of-mass energy of 3.773 GeV with the BESIII detector operated at the BEPCII collider, we perform an analysis of the semileptonic decays D^{0(+)}→π^{-(0)}μ^{+}ν_{μ}. The branching fractions of D^{0}→π^{-}μ^{+}ν_{μ} and D^{+}→π^{0}μ^{+}ν_{μ} are measured to be (0.272±0.008_{stat}±0.006_{syst})% and (0.350±0.011_{stat}±0.010_{syst})%, respectively, where the former is of much improved precision compared to previous results and the latter is determined for the first time. Using these results along with previous BESIII measurements of D^{0(+)}→π^{-(0)}e^{+}ν_{e}, we calculate the branching fraction ratios to be R^{0}≡B_{D^{0}→π^{-}μ^{+}ν_{μ}}/B_{D^{0}→π^{-}e^{+}ν_{e}}=0.922±0.030_{stat}±0.022_{syst} and R^{+}≡B_{D^{+}→π^{0}μ^{+}ν_{μ}}/B_{D^{+}→π^{0}e^{+}ν_{e}}=0.964±0.037_{stat}±0.026_{syst}, which are compatible with the theoretical expectation of lepton flavor universality within 1.7σ and 0.5σ, respectively. We also examine the branching fraction ratios in different four-momentum transfer square regions, and find no significant deviations from the standard model predictions.

Measurement of the Absolute Branching Fraction of the Inclusive Decay Λ_{c}^{+}→Λ+X

Based on an e^{+}e^{-} collision data sample corresponding to an integrated luminosity of 567  pb^{-1} taken at the center-of-mass energy of sqrt[s]=4.6  GeV with the BESIII detector, we measure the absolute branching fraction of the inclusive decay Λ_{c}^{+}→Λ+X to be B(Λ_{c}^{+}→Λ+X)=(38.2_{-2.2}^{+2.8}±0.9)% using the double-tag method, where X refers to any possible final state particles. In addition, we search for direct CP violation in the charge asymmetry of this inclusive decay for the first time, and obtain A_{CP}≡[B(Λ_{c}^{+}→Λ+X)-B(Λ[over ¯]_{c}^{-}→Λ[over ¯]+X)]/[B(Λ_{c}^{+}→Λ+X)+B(Λ[over ¯]_{c}^{-}→Λ[over ¯]+X)]=(2.1_{-6.6}^{+7.0}±1.6)%, a statistically limited result with no evidence of CP violation.

Observation of a_{0}^{0}(980)-f_{0}(980) Mixing

We report the first observation of a_{0}^{0}(980)-f_{0}(980) mixing in the decays of J/ψ→ϕf_{0}(980)→ϕa_{0}^{0}(980)→ϕηπ^{0} and χ_{c1}→a_{0}^{0}(980)π^{0}→f_{0}(980)π^{0}→π^{+}π^{-}π^{0}, using data samples of 1.31×10^{9}  J/ψ events and 4.48×10^{8}  ψ(3686) events accumulated with the BESIII detector. The signals of f_{0}(980)→a_{0}^{0}(980) and a_{0}^{0}(980)→f_{0}(980) mixing are observed at levels of statistical significance of 7.4σ and 5.5σ, respectively. The corresponding branching fractions and mixing intensities are measured and the constraint regions on the coupling constants, g_{a_{0}K^{+}K^{-}} and g_{f_{0}K^{+}K^{-}}, are estimated. The results improve the understanding of the nature of a_{0}^{0}(980) and f_{0}(980).

Precision Study of η^{'}→γπ^{+}π^{-} Decay Dynamics

Using a low background data sample of 9.7×10^{5}  J/ψ→γη^{'}, η^{'}→γπ^{+}π^{-} events, which are 2 orders of magnitude larger than those from the previous experiments, recorded with the BESIII detector at BEPCII, the decay dynamics of η^{'}→γπ^{+}π^{-} are studied with both model-dependent and model-independent approaches. The contributions of ω and the ρ(770)-ω interference are observed for the first time in the decays η^{'}→γπ^{+}π^{-} in both approaches. Additionally, a contribution from the box anomaly or the ρ(1450) resonance is required in the model-dependent approach, while the process specific part of the decay amplitude is determined in the model-independent approach.

Determination of the Spin and Parity of the Z_{c}(3900)

The spin and parity of the Z_{c}(3900)^{±} state are determined to be J^{P}=1^{+} with a statistical significance larger than 7σ over other quantum numbers in a partial wave analysis of the process e^{+}e^{-}→π^{+}π^{-}J/ψ. We use a data sample of 1.92  fb^{-1} accumulated at sqrt[s]=4.23 and 4.26 GeV with the BESIII experiment. When parametrizing the Z_{c}(3900)^{±} with a Flatté-like formula, we determine its pole mass M_{pole}=(3881.2±4.2_{stat}±52.7_{syst})  MeV/c^{2} and pole width Γ_{pole}=(51.8±4.6_{stat}±36.0_{syst})  MeV. We also measure cross sections for the process e^{+}e^{-}→Z_{c}(3900)^{+}π^{-}+c.c.→J/ψπ^{+}π^{-} and determine an upper limit at the 90% confidence level for the process e^{+}e^{-}→Z_{c}(4020)^{+}π^{-}+c.c.→J/ψπ^{+}π^{-}.

Observation of Λ_{c}^{+}→nK_{S}^{0}π^{+}

We report the first direct measurement of decays of the Λ_{c}^{+} baryon involving the neutron. The analysis is performed using 567  pb^{-1} of e^{+}e^{-} collision data collected at sqrt[s]=4.599  GeV with the BESIII detector at the BEPCII collider. We observe the decay Λ_{c}^{+}→nK_{S}^{0}π^{+} and measure the absolute branching fraction to be B(Λ_{c}^{+}→nK_{S}^{0}π^{+})=[1.82±0.23(stat)±0.11(syst)]%. A comparison to B[Λ_{c}^{+}→p(K[over ¯]π)^{0}] provides an important test of isospin symmetry and final state interactions.

Precise Measurement of the e^{+}e^{-}→π^{+}π^{-}J/ψ Cross Section at Center-of-Mass Energies from 3.77 to 4.60 GeV

The cross section for the process e^{+}e^{-}→π^{+}π^{-}J/ψ is measured precisely at center-of-mass energies from 3.77 to 4.60 GeV using 9  fb^{-1} of data collected with the BESIII detector operating at the BEPCII storage ring. Two resonant structures are observed in a fit to the cross section. The first resonance has a mass of (4222.0±3.1±1.4)  MeV/c^{2} and a width of (44.1±4.3±2.0)  MeV, while the second one has a mass of (4320.0±10.4±7.0)  MeV/c^{2} and a width of (101.4_{-19.7}^{+25.3}±10.2)  MeV, where the first errors are statistical and second ones are systematic. The first resonance agrees with the Y(4260) resonance reported by previous experiments. The precision of its resonant parameters is improved significantly. The second resonance is observed in e^{+}e^{-}→π^{+}π^{-}J/ψ for the first time. The statistical significance of this resonance is estimated to be larger than 7.6σ. The mass and width of the second resonance agree with the Y(4360) resonance reported by the BABAR and Belle experiments within errors. Finally, the Y(4008) resonance previously observed by the Belle experiment is not confirmed in the description of the BESIII data.

Evidence of Two Resonant Structures in e^{+}e^{-}→π^{+}π^{-}h_{c}

The cross sections of e^{+}e^{-}→π^{+}π^{-}h_{c} at center-of-mass energies from 3.896 to 4.600 GeV are measured using data samples collected with the BESIII detector operating at the Beijing Electron Positron Collider. The cross sections are found to be of the same order of magnitude as those of e^{+}e^{-}→π^{+}π^{-}J/ψ and e^{+}e^{-}→π^{+}π^{-}ψ(2S), but the line shape is inconsistent with the Y states observed in the latter two modes. Two structures are observed in the e^{+}e^{-}→π^{+}π^{-}h_{c} cross sections around 4.22 and 4.39  GeV/c^{2}, which we call Y(4220) and Y(4390), respectively. A fit with a coherent sum of two Breit-Wigner functions results in a mass of (4218.4_{-4.5}^{+5.5}±0.9)  MeV/c^{2} and a width of (66.0_{-8.3}^{+12.3}±0.4)  MeV for the Y(4220), and a mass of (4391.5_{-6.8}^{+6.3}±1.0)  MeV/c^{2} and a width of (139.5_{-20.6}^{+16.2}±0.6)  MeV for the Y(4390), where the first uncertainties are statistical and the second ones systematic. The statistical significance of Y(4220) and Y(4390) is 10σ over one structure assumption.

Amplitude Analysis of the Decays η^{'}→π^{+}π^{-}π^{0} and η^{'}→π^{0}π^{0}π^{0}

Based on a sample of 1.31×10^{9}  J/ψ events collected with the BESIII detector, an amplitude analysis of the isospin-violating decays η^{'}→π^{+}π^{-}π^{0} and η^{'}→π^{0}π^{0}π^{0} is performed. A significant P-wave contribution from η^{'}→ρ^{±}π^{∓} is observed for the first time in η^{'}→π^{+}π^{-}π^{0}. The branching fraction is determined to be B(η^{'}→ρ^{±}π^{∓})=(7.44±0.60±1.26±1.84)×10^{-4}, where the first uncertainty is statistical, the second systematic, and the third model dependent. In addition to the nonresonant S-wave component, there is a significant σ meson component. The branching fractions of the combined S-wave components are determined to be B(η^{'}→π^{+}π^{-}π^{0})_{S}=(37.63±0.77±2.22±4.48)×10^{-4} and B(η^{'}→π^{0}π^{0}π^{0})=(35.22±0.82±2.54)×10^{-4}, respectively. The latter one is consistent with previous BESIII measurements.

Measurement of Singly Cabibbo Suppressed Decays Λ_{c}^{+}→pπ^{+}π^{-} and Λ_{c}^{+}→pK^{+}K^{-}

Using 567  pb^{-1} of data collected with the BESIII detector at a center-of-mass energy of sqrt[s]=4.599  GeV, near the Λ_{c}^{+}Λ[over ¯]_{c}^{-} threshold, we study the singly Cabibbo-suppressed decays Λ_{c}^{+}→pπ^{+}π^{-} and Λ_{c}^{+}→pK^{+}K^{-}. By normalizing with respect to the Cabibbo-favored decay Λ_{c}^{+}→pK^{-}π^{+}, we obtain ratios of branching fractions: [B(Λ_{c}^{+}→pπ^{+}π^{-})/B(Λ_{c}^{+}→pK^{-}π^{+})]=(6.70±0.48±0.25)%, [B(Λ_{c}^{+}→pϕ)/B(Λ_{c}^{+}→pK^{-}π^{+})]=(1.81±0.33±0.13)%, and [B(Λ_{c}^{+}→pK^{+}K_{non-ϕ}^{-})/B(Λ_{c}^{+}→pK^{-}π^{+})]=(9.36±2.22±0.71)×10^{-3}, where the uncertainties are statistical and systematic, respectively. The absolute branching fractions are also presented. Among these measurements, the decay Λ_{c}^{+}→pπ^{+}π^{-} is observed for the first time, and the precision of the branching fraction for Λ_{c}^{+}→pK^{+}K_{non-ϕ}^{-} and Λ_{c}^{+}→pϕ is significantly improved.

Identification of Natural Infections in Sheep/Goats with HoBi-like Pestiviruses in China

The natural infections of HoBi-like pestiviruses in cattle have been reported in South America, Europe and Asia. In China, although the detections of HoBi-like pestivirus have been reported, the epidemiological investigation was limited. From January 2014 to October 2015, several flocks of sheep/goats in Henan province in central China suffered respiratory diseases which were recovered slowly after antibiotics treatment. To test whether it is the HoBi-like pestivirus caused this symptom, 49 serum samples and 22 nasal swabs were then collected for analysis by serology and RT-PCR. Serological result revealed that prevalence of pestivirus in small ruminants was 12.2% (6/49) in central China. Sequence analysis of partial 5'-UTR nucleotides of pestivirus-positive samples suggested that HoBi-like pestivirus might have circulated in sheep/goats of China for a period and have evolved into new genotype clusters. It is apparent that the study provides the molecular evidence of natural infections in goat/sheep species with HoBi-like pestiviruses in China.

Observation of an Anomalous Line Shape of the η^{'}π^{+}π^{-} Mass Spectrum near the pp[over ¯] Mass Threshold in J/ψ→γη^{'}π^{+}π^{-}

Using 1.09×10^{9} J/ψ events collected by the BESIII experiment in 2012, we study the J/ψ→γη^{'}π^{+}π^{-} process and observe a significant abrupt change in the slope of the η^{'}π^{+}π^{-} invariant mass distribution at the proton-antiproton (pp[over ¯]) mass threshold. We use two models to characterize the η^{'}π^{+}π^{-} line shape around 1.85  GeV/c^{2}: one that explicitly incorporates the opening of a decay threshold in the mass spectrum (Flatté formula), and another that is the coherent sum of two resonant amplitudes. Both fits show almost equally good agreement with data, and suggest the existence of either a broad state around 1.85  GeV/c^{2} with strong couplings to the pp[over ¯] final states or a narrow state just below the pp[over ¯] mass threshold. Although we cannot distinguish between the fits, either one supports the existence of a pp[over ¯] moleculelike state or bound state with greater than 7σ significance.

Observation of h_{c} Radiative Decay h_{c}→γη^{'} and Evidence for h_{c}→γη

A search for radiative decays of the P-wave spin singlet charmonium resonance h_{c} is performed based on 4.48×10^{8} ψ^{'} events collected with the BESIII detector operating at the BEPCII storage ring. Events of the reaction channels h_{c}→γη^{'} and γη are observed with a statistical significance of 8.4σ and 4.0σ, respectively, for the first time. The branching fractions of h_{c}→γη^{'} and h_{c}→γη are measured to be B(h_{c}→γη^{'})=(1.52±0.27±0.29)×10^{-3} and B(h_{c}→γη)=(4.7±1.5±1.4)×10^{-4}, respectively, where the first errors are statistical and the second are systematic uncertainties.

Observation of the Singly Cabibbo-Suppressed Decay D^{+}→ωπ^{+} and Evidence for D^{0}→ωπ^{0}

Based on 2.93  fb^{-1} e^{+}e^{-} collision data taken at center-of-mass energy of 3.773 GeV by the BESIII detector, we report searches for the singly Cabibbo-suppressed decays D^{+}→ωπ^{+} and D^{0}→ωπ^{0}. A double tag technique is used to measure the absolute branching fractions B(D^{+}→ωπ^{+})=(2.79±0.57±0.16)×10^{-4} and B(D^{0}→ωπ^{0})=(1.17±0.34±0.07)×10^{-4}, with statistical significances of 5.5σ and 4.1σ, where the first and second uncertainties are statistical and systematic, respectively.

Measurements of Absolute Hadronic Branching Fractions of the Λ_{c}^{+} Baryon

We report the first measurement of absolute hadronic branching fractions of Λ_{c}^{+} baryon at the Λ_{c}^{+}Λ[over ¯]_{c}^{-} production threshold, in the 30 years since the Λ_{c}^{+} discovery. In total, 12 Cabibbo-favored Λ_{c}^{+} hadronic decay modes are analyzed with a double-tag technique, based on a sample of 567  pb^{-1} of e^{+}e^{-} collisions at sqrt[s]=4.599  GeV recorded with the BESIII detector. A global least-squares fitter is utilized to improve the measured precision. Among the measurements for twelve Λ_{c}^{+} decay modes, the branching fraction for Λ_{c}^{+}→pK^{-}π^{+} is determined to be (5.84±0.27±0.23)%, where the first uncertainty is statistical and the second is systematic. In addition, the measurements of the branching fractions of the other 11 Cabibbo-favored hadronic decay modes are significantly improved.

Measurement of Azimuthal Asymmetries in Inclusive Charged Dipion Production in e^{+}e^{-} Annihilations at sqrt[s]=3.65 GeV

We present a measurement of the azimuthal asymmetries of two charged pions in the inclusive process e^{+}e^{-}→ππX, based on a data set of 62  pb^{-1} at the center-of-mass energy of 3.65 GeV collected with the BESIII detector. These asymmetries can be attributed to the Collins fragmentation function. We observe a nonzero asymmetry, which increases with increasing pion momentum. As our energy scale is close to that of the existing semi-inclusive deep inelastic scattering experimental data, the measured asymmetries are important inputs for the global analysis of extracting the quark transversity distribution inside the nucleon and are valuable to explore the energy evolution of the spin-dependent fragmentation function.

Observation of a Neutral Structure near the DD[over ¯]^{*} Mass Threshold in e^{+}e^{-}→(DD[over ¯]^{*})^{0}π^{0} at sqrt[s]=4.226 and 4.257 GeV

A neutral structure in the DD[over ¯]^{*} system around the DD[over ¯]^{*} mass threshold is observed with a statistical significance greater than 10σ in the processes e^{+}e^{-}→D^{+}D^{*-}π^{0}+c.c. and e^{+}e^{-}→D^{0}D[over ¯]^{*0}π^{0}+c.c. at sqrt[s]=4.226 and 4.257 GeV in the BESIII experiment. The structure is denoted as Z_{c}(3885)^{0}. Assuming the presence of a resonance, its pole mass and width are determined to be [3885.7_{-5.7}^{+4.3}(stat)±8.4(syst)]  MeV/c^{2} and [35_{-12}^{+11}(stat)±15(syst)]  MeV, respectively. The Born cross sections are measured to be σ[e^{+}e^{-}→Z_{c}(3885)^{0}π^{0},Z_{c}(3885)^{0}→DD[over ¯]^{*}]=[77±13(stat)±17(syst)]  pb at 4.226 GeV and [47±9(stat)±10(syst)]  pb at 4.257 GeV. The ratio of decay rates B[Z_{c}(3885)^{0}→D^{+}D^{*-}+c.c.]/B[Z_{c}(3885)^{0}→D^{0}D[over ¯]^{*0}+c.c.] is determined to be 0.96±0.18(stat)±0.12(syst), consistent with no isospin violation in the process, Z_{c}(3885)^{0}→DD[over ¯]^{*}.

Measurement of the Absolute Branching Fraction for Λ_{c}^{+}→Λe^{+}ν_{e}

We report the first measurement of the absolute branching fraction for Λ_{c}^{+}→Λe^{+}ν_{e}. This measurement is based on 567  pb^{-1} of e^{+}e^{-} annihilation data produced at sqrt[s]=4.599  GeV, which is just above the Λ_{c}^{+}Λ[over ¯]_{c}^{-} threshold. The data were collected with the BESIII detector at the BEPCII storage rings. The branching fraction is determined to be B(Λ_{c}^{+}→Λe^{+}ν_{e})=[3.63±0.38(stat)±0.20(syst)]%, representing a significant improvement in precision over the current indirect determination. As the branching fraction for Λ_{c}^{+}→Λe^{+}ν_{e} is the benchmark for those of other Λ_{c}^{+} semileptonic channels, our result provides a unique test of different theoretical models, which is the most stringent to date.

Observation of a Neutral Charmoniumlike State Z_{c}(4025)^{0} in e^{+}e^{-}→(D^{*}D[over ¯]^{*})^{0}π^{0}

We report a study of the process e^{+}e^{-}→(D^{*}D[over ¯]^{*})^{0}π^{0} using e^{+}e^{-} collision data samples with integrated luminosities of 1092 pb^{-1} at sqrt[s]=4.23 GeV and 826 pb^{-1} at sqrt[s]=4.26 GeV collected with the BESIII detector at the BEPCII storage ring. We observe a new neutral structure near the (D^{*}D[over ¯]^{*})^{0} mass threshold in the π^{0} recoil mass spectrum, which we denote as Z_{c}(4025)^{0}. Assuming a Breit-Wigner line shape, its pole mass and pole width are determined to be (4025.5_{-4.7}^{+2.0}±3.1) MeV/c^{2} and (23.0±6.0±1.0) MeV, respectively. The Born cross sections of e^{+}e^{-}→Z_{c}(4025)^{0}π^{0}→(D^{*}D[over ¯]^{*})^{0}π^{0} are measured to be (61.6±8.2±9.0) pb at sqrt[s]=4.23 GeV and (43.4±8.0±5.4) pb at sqrt[s]=4.26 GeV. The first uncertainties are statistical and the second are systematic.

Observation of Z_{c}(3900)^{0} in e^{+}e^{-}→π^{0}π^{0}J/ψ

Using a data sample collected with the BESIII detector operating at the BEPCII storage ring, we observe a new neutral state Z_{c}(3900)^{0} with a significance of 10.4σ. The mass and width are measured to be 3894.8±2.3±3.2  MeV/c^{2} and 29.6±8.2±8.2  MeV, respectively, where the first error is statistical and the second systematic. The Born cross section for e^{+}e^{-}→π^{0}π^{0}J/ψ and the fraction of it attributable to π^{0}Z_{c}(3900)^{0}→π^{0}π^{0}J/ψ in the range E_{c.m.}=4.19-4.42  GeV are also determined. We interpret this state as the neutral partner of the four-quark candidate Z_{c}(3900)^{±}.

Observation and Spin-Parity Determination of the X(1835) in J/ψ→γK_{S}^{0}K_{S}^{0}η

We report an observation of the process J/ψ→γX(1835)→γK_{S}^{0}K_{S}^{0}η at low K_{S}^{0}K_{S}^{0} mass with a statistical significance larger than 12.9σ using a data sample of 1.31×10^{9} J/ψ events collected with the BESIII detector. In this region of phase space the K_{S}^{0}K_{S}^{0} system is dominantly produced through the f_{0}(980). By performing a partial wave analysis, we determine the spin parity of the X(1835) to be J^{PC}=0^{-+}. The mass and width of the observed X(1835) are 1844±9(stat)_{-25}^{+16}(syst)  MeV/c^{2} and 192_{-17}^{+20}(stat)_{-43}^{+62}(syst)  MeV, respectively, which are consistent with the results obtained by BESIII in the channel J/ψ→γπ^{+}π^{-}η^{'}.

Observation of the ψ(1 3D2) State in e+e-→π+π-γχc1 at BESIII

We report the observation of the X(3823) state in the process e+e-→π+π-X(3823)→π+π-γχc1 with a statistical significance of 6.2σ, in data samples at center-of-mass energies sqrt[s]=4.230, 4.260, 4.360, 4.420, and 4.600 GeV collected with the BESIII detector at the BEPCII electron positron collider. The measured mass of the X(3823) state is (3821.7±1.3±0.7)  MeV/c2, where the first error is statistical and the second systematic, and the width is less than 16 MeV at the 90% confidence level. The products of the Born cross sections for e+e-→π+π-X(3823) and the branching ratio B[X(3823)→γχc1,c2] are also measured. These measurements are in good agreement with the assignment of the X(3823) state as the ψ(1 3D2) charmonium state.

An assessment survey of anti-tuberculosis drug management in Cambodia

SETTING

One hundred and seven public health facilities with tuberculosis (TB) service and 66 private pharmacies in 14 provinces.

OBJECTIVES

To assess the knowledge, attitudes and practices (KAP) of TB service providers, new smear-positive pulmonary TB out-patients and drug storekeepers, to document practices in the public sector TB drug procurement system, to measure TB drug availability in private pharmacies and to compare public and private sector TB drug prices with international prices.

DESIGN

Documents and treatment record reviews, inventory checks and structured interviews.

RESULTS

The prescribing practices of the TB service providers were acceptable. The level of new smear-positive TB out-patients' knowledge of TB treatment was high. The storekeepers' inventory practices for TB drugs indicated a need for improvement. Various TB drugs were available in the private pharmacies. TB drug prices in the public sector were similar to international reference prices, although they were higher than the Global TB Drug Facility prices.

CONCLUSIONS

An indicator-based anti-tuberculosis drug management assessment survey can measure the current situation and quality of DOTS, identify any weaknesses or changes in practice from the norm, and simultaneously serve as a basis for training of TB service providers and storekeepers.

Cardiopulmonary resuscitation with a hydraulic-pneumatic band

Improved blood flow during cardiopulmonary resuscitation (CPR) has been shown to enhance survival from cardiac arrest. Chest compression with a circumferential pneumatic vest enhances blood flow, but the size, weight, and energy consumption of the inflation system limit its portability and, thereby, have made clinical studies difficult. The purpose of this investigation was to study an improved circumferential chest compression device that uses a constricting band that is pneumatically actuated. The constricting band applies its force to a hydraulic cushion that contacts the anterior and lateral aspects of the chest. The hydraulic cushion transfers the circumferential constriction to inward force. CPR was performed on subjects 5 mins after induction of ventricular fibrillation, with the hydraulic-pneumatic band system (HB-CPR), with a pneumatic vest system (PV-CPR), and with standard manual CPR (S-CPR), each done for 2 mins in randomized order. Aortic and right atrial pressures were measured with micromanometers. Coronary perfusion pressure was calculated as the mean difference between the aortic and right atrial pressures during the release phase of chest compression. Aortic pressure and coronary perfusion pressure with HB-CPR and PV-CPR were improved over S-CPR, and HB-CPR produced comparable pressures to those of PV-CPR. The system for performing HB-CPR, however, was substantially lighter (10 vs. 50 kg) and consumed less energy (300 vs. 1000 watts) than that for PV-CPR. Thus, HB-CPR appears to produce a similar improvement in hemodynamics over S-CPR as PV-CPR but may be more portable than PV-CPR. Therefore, HB-CPR may allow larger scale testing of circumferential chest compression approaches.

High-level nuclear NF-kappa B and Oct-2 is a common feature of cultured Hodgkin/Reed-Sternberg cells

There is a considerable lack of understanding about the common molecular defects that form the basis for the occurrence of Hodgkin's lymphoma. Despite a number of molecular tools used thus far in immunophenotypic and karyotypic studies, it has not been possible to establish a single common trait among various Hodgkin (H)-cell lines or primary tumor cells that would allow classification into a particular hematopoietic lineage. With this study, we demonstrate that a characteristic expression pattern of transcription factors provides a unifying principle. Seven different cell lines derived from patients with Hodgkin's disease (HD), as well as primary H/Reed-Sternberg (RS) cells isolated from the pericardial fluid of a patient with HD, were compared with a number of hematopoietic and nonhematopoietic cell lines for the expression of Oct-2, a tissue-specific transcription factor normally restricted to B cells, and nuclear factor kappa B (NF-kappa B), an inducible transcription factor. Regardless of the heterogeneous phenotypes and genotypes of the H cell lines, which varied inconsistently between B-cell-, T-cell-, or monocyte-like properties, all H cells tested displayed expression of Oct-2 protein at levels comparable to those seen in B cells. Furthermore, all cell lines showed an abundant constitutive nuclear NF-kappa B activity. Interestingly, anaplastic large-cell lymphoma (ALCL) cell lines, which have many features in common with H/RS cells, were devoid constitutive nuclear NF-kappa B activity. Unlike the constitutive NF-kappa B activity known for B cells, which mainly consists of the p50 and c-Rel or RelB subunits, we demonstrate by antibody supershifting experiments that H cells contain constitutive nuclear p50 and p65, the dimeric NF-kappa B normally observed only for limited time intervals after stimulation with diverse inducers. Additionally, some H-cell lines also displayed nuclear c-Rel activity, whereas RelB or p52 were not detected as part of the constitutive activity. The expression pattern of Oct-2 and NF-kappa B appears to be a unifying and characteristic property of H cells and might explain the deregulated expression of various cytokines leading to the clinical and pathologic manifestations of HD.

G protein subunit G alpha 16 expression is restricted to progenitor B cells during human B-cell differentiation

Recently G alpha 16, a new guanosine triphosphate (GTP) binding protein alpha subunit has been described to be specifically expressed in human hematopoietic cells. Expression of G alpha 16 was observed in human cell lines of myelomonocytic and T-lymphocytic origin, but not in human B-cell lines Raji and IM9. We studied the expression of G alpha 16 in human B cells corresponding to different stages of B-cell differentiation by means of reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. The human Burkitt's lymphoma cell lines Raji, Ramos, BJAB, the lymphoblastoid cell line SKW6.4, and the plasmocytoma cell line U266 were devoid of G alpha 16. In contrast, G alpha 16 was detected in the human progenitor B cell lines Reh and Nalm-6. Using the mu+, k- cell line BLIN-1 (pre-B cell phenotype) and its derived subclone 1E8 (surface mu+, k+; B-cell phenotype) G alpha 16 expression was found to disappear on transition from pre-B to B-cell differentiation stage. The analysis of a broad panel of human neoplastic B lymphocytes ranging from progenitor B-acute lymphatic leukemia (pre-pre-B-ALL), common acute leukemias (cALL), pre-B-ALL, mature B-ALL to low grade B-cell lymphoma (chronic lymphocytic leukemia of B-cell type, leukemic centrocytic non-Hodgkins lymphoma [NHL], hairy cell leukemia) showed that G alpha 16 expression is limited to progenitor and pre-B-ALL cells. Therefore, we conclude that within B-cell differentiation, G alpha 16 is expressed solely during early B cell ontogeny and downregulated during differentiation. Thus, G alpha 16 might be an important regulator involved in signaling processes in progenitor B cells.

T‐cell receptor α chain germline gene polymorphisms in multiple sclerosis

It has been proposed that genetic predisposition to multiple sclerosis (MS) and other diseases with autoimmune features is conferred by T-cell receptor (TcR) genes in addition to HLA class II genes. Although a family study has suggested linkage of susceptibility to MS to TcR genes, reports of disease associations with restriction fragment length polymorphism (RFLPI-defined alleles of TcR genes have been difficult to confirm, including a report of association of MS with TcR ß-chain gene RFLPs. We report here the distribution of three sets of RFLPs of the TcR α chain genes. Similar frequencies in patients and controls were observed for TaqI and Bgl II RFLPs of the TcR α constant segment (Cα), the latter earlier reported to be associated with MS. A previously reported MS-associated PssI RFLP of the Vα12 and Cα gene segments could not be confirmed. Our results indicate that these seemingly polymorphic restriction fragments are possibly the results of incomplete enzymatic cleavage of DNA in the RFLP analysis. We conclude that no convincing evidence exists for the association of MS with RFLPs of the TcR α or β chain genes.

No association with germline T cell receptor beta-chain gene alleles or haplotypes in Swedish patients with multiple sclerosis

Multiple sclerosis (MS) has been reported to be associated with restriction fragment length polymorphism (RFLP)-defined alleles of the T cell receptor (TcR) alpha- and beta-chain genes. One hundred patients with MS, 23 with primarily chronic progressive MS and 77 with relapsing/remitting MS, as well as 100 controls were investigated with RFLP analysis of the V beta 8, V beta 11 and C beta TcR gene segments. No association was found with allelic patterns or, contrary to a previous report (Beall et al. (1989) J. Neuroimmunol. 21, 59-66), TcR beta-chain gene haplotypes. Subgrouping of patients according to clinical form of disease or MS-associated HLA class II alleles also failed to show associations to TcR beta-chain RFLPs. Thus, our results fail to confirm that TcR beta-chain gene haplotypes confer susceptibility to MS.