Tracing the Transboundary Transport of Mercury to the Tibetan Plateau Using Atmospheric Mercury Isotopes

Deposition of atmospheric mercury (Hg) is the most important Hg source on the high-altitude Himalayas and Tibetan Plateau. Herein, total gaseous Hg (TGM) at an urban and a forest site on the Tibetan Plateau was collected respectively from May 2017 to October 2018, and isotopic compositions were measured to clarify the influences of landforms and monsoons on the transboundary transport of atmospheric Hg to the Tibetan Plateau. The transboundary transported anthropogenic emissions mainly originated over Indo-Gangetic Plain and carried over the Himalayas by convective storms and mid-tropospheric circulation, contributing over 50% to the TGM at the Lhasa urban site, based on the binary mixing model of isotopes. In contrast, during the transport of TGM from South Asia with low altitude, the uptake by evergreen forest in Yarlung Zangbo Grand Canyon largely decreased the TGM level and shifted isotopic compositions in TGM at the Nyingchi forest site, which are located at the high-altitude end of the canyon. Our results provided direct evidence from Hg isotopes to reveal the distinct patterns of transboundary transport to the Tibetan Plateau shaped by landforms and climates, which is critical to fully understand the biogeochemical cycling of Hg in the high-altitude regions.

Analysis of Neutral B-Meson Decays into Two Muons

Branching fraction and effective lifetime measurements of the rare decay B_{s}^{0}→μ^{+}μ^{-} and searches for the decays B^{0}→μ^{+}μ^{-} and B_{s}^{0}→μ^{+}μ^{-}γ are reported using proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a luminosity of 9  fb^{-1}. The branching fraction B(B_{s}^{0}→μ^{+}μ^{-})=(3.09_{-0.43-0.11}^{+0.46+0.15})×10^{-9} and the effective lifetime τ(B_{s}^{0}→μ^{+}μ^{-})=2.07±0.29±0.03  ps are measured, where the first uncertainty is statistical and the second systematic. No significant signal for B^{0}→μ^{+}μ^{-} and B_{s}^{0}→μ^{+}μ^{-}γ decays is found and upper limits B(B^{0}→μ^{+}μ^{-})<2.6×10^{-10} and B(B_{s}^{0}→μ^{+}μ^{-}γ)<2.0×10^{-9} at the 95% C.L. are determined, where the latter is limited to the range m_{μμ}>4.9  GeV/c^{2}. The results are in agreement with the standard model expectations.

Computational Insights into the Allosteric Effect and Dynamic Structural Features of the SARS‐COV‐2 Spike Protein

Invited for the cover of this issue are Aiqian Zhang, Jianjie Fu, Guibin Jiang, and co‐workers at the Chinese Academy of Sciences. The image depicts the molecular recognition of human angiotensin‐converting enzyme 2 by the SARS‐COV‐2 spike protein. Read the full text of the article at10.1002/chem.202104215.

[Digital orthopedics technology leads the new development direction of arthroplasty]

Digital orthopedics technology is a new interdisciplinary subject, known as the third technological wave in the field of orthopedics. The development direction of arthroplasty is focused on hoping to improve the long-term prognosis of patients by imitating more natural kinematics and optimizing implant positioning strategies. At present, various digital orthopedic technologies such as virtual reality technology, navigation assistance systems, and patient-specific instrumentation (PSI) and robot-assisted surgery in joint surgery are in full swing. In this article, relevant domestic and foreign literature were extensively reviewed and the author's own experiences were summarize, and the advantages, disadvantages, clinical efficacy and future prospects of the above-mentioned various technologies were evaluated too.

Computational Insights on Allosteric Effect and Dynamic Structural Feature of SARS-COV-2 Spike Protein

COVID-19 caused by SARS-COV-2 is currently continuing to surge globally. The spike (S) protein is the key protein of SARS-COV-2 that recognizes and binds to the host target ACE2. In this study, molecular dynamics simulation was used to elucidate the allosteric effect of S protein. The binding of ACE2 caused a centripetal movement of the receptor-binding domain of the S protein. The dihedral changes of Phe329 and Phe515 played a key role in this process. Two potential cleavage sites S1/S2 and S2' were exposed on the surface after the binding of ACE2. The binding affinity of SARS-COV-2 S protein and ACE2 was significantly higher than that of SARS-COV. This was mainly due to the mutation of Asp480 in SARS-COV to Ser494 in SARS-COV-2, which greatly weakened the electrostatic repulsion. The result provides theoretical basis for the SARS-COV-2 infection and aids the development of biosensors and detection reagents.

A combination of fecal calprotectin and human beta-defensin 2 facilitates diagnosis and monitoring of inflammatory bowel disease

Inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) show a large overlap in clinical presentation, which presents diagnostic challenges. As a consequence, invasive and burdensome endoscopies are often used to distinguish between IBD and IBS. Here, we aimed to develop a noninvasive fecal test that can distinguish between IBD and IBS and reduce the number of endoscopies.We used shotgun metagenomic sequencing to analyze the composition and function of gut microbiota of 169 IBS patients, 447 IBD patients and 1044 population controls and measured fecal Calprotectin (FCal), human beta defensin 2 (HBD2), and chromogranin A (CgA) in these samples. These measurements were used to construct training sets (75% of data) for logistic regression and machine learning models to differentiate IBS from IBD and inactive from active IBD. The results were replicated on test sets (remaining 25% of the data) and microbiome data obtained using 16S sequencing.Fecal HBD2 showed high sensitivity and specificity for differentiating between IBD and IBS (sensitivity = 0.89, specificity = 0.76), while the inclusion of microbiome data with biomarkers (HBD2 and FCal) showed a potential for improvement in predictive power (optimal sensitivity = 0.87, specificity = 0.93). Shotgun sequencing-based models produced comparable results using 16S-sequencing data. HBD2 and FCal were found to have predictive power for IBD disease activity (AUC ≈ 0.7).HBD2 is a novel biomarker for IBD in patients with gastro-intestinal complaints, especially when used in combination with FCal and potentially in combination with gut microbiome data.

Promoting effect of the recombinant resuscitation promoting factors-2 of Rhodococcus erythropolis on petroleum degradation and cultivable bacterial diversities of the oil-contaminated soils

Resuscitation-promoting factors (Rpfs) belong to peptidoglycan hydrolases, which participate in recovery of dormant cells and promoting bacteria growth. In this study, the resuscitation promoting factor rpf2 gene of Rhodococcus erythropolis KB1 was expressed in Escherichia coli and purified by Ni²⁺ affinity chromatography. The purified recombinant fusion protein Rpf2 showed a closely 50 kDa band on sodium dodecyl sulphate polyacrylamide gel electrophoresis. The protein showed muralytic activity, with a specific activity of 1503 ± 123 U mg^-1 when determined with 4-methylumbelliferyl-β-d-N, N',N″-triacetotri-ylchitoside as substrate. It also showed protease activity when measured with azocasein as substrate, with a specific activity of 1528 ± 411 U mg^-1 . The addition of the recombinant Rpf2 protein significantly increased petroleum degradation efficiency of the indigenous micro-organisms and the petroleum degradation rates increased from 30·86 to 43·45%, 45·20 and 49·23% in the treatment groups. The recombinant protein also increased the petroleum-degrading bacterial diversities enriched from the contaminated soils. The cultivable bacterial flora of the treatment groups supplemented with different concentrations of Rpf2 increased from 82 genera in 9 phyla to 116 genera in 16 phyla and 138 genera in 16 phyla respectively. Thirteen extra petroleum-degrading bacteria strains were isolated from the petroleum-contaminated soils in the groups containing the recombinant Rpf2.

Role of hypobromous acid in the transformation of polycyclic aromatic hydrocarbons during chlorination

Hypobromous acid (HOBr), a highly reactive active species, can be formed and impact reaction processes with organic pollutants in source water during chlorination disinfection of the water containing bromide (Br-). In this study, we investigated the transformation kinetics of 10 parent polycyclic aromatic hydrocarbons (PAHs) and formation mechanisms of transformation products in the presence of Br- during chlorination. The results indicated that HOBr can accelerate the processes of electrophilic substitution (ES) and single electron transfer (ET) reactions in PAHs, and the second-order rate constants of HOBr are 10²-10³ times higher than those of hypochlorous acid (HOCl) with PAHs. HOBr was more conductive to induce ES reactions than HOCl. In water containing Br-, HOBr and HOCl dominate the reaction processes with PAHs, although other active bromine species may still affect reaction processes. In terms of transformation products, higher reactivity of HOBr results from faster formation of oxygenated PAHs (OPAHs) and halogenated PAHs (HPAHs) than HOCl. As an example of 3 model PAHs, anthracene transforms faster to its oxygenated products at a higher concentration, while pyrene and fluorene transform faster to halogenated products. These fundamental results were essential to understanding the transformation kinetics of PAHs and the formation of toxic disinfection by-products in the presence of Br-.

Early pregnancy loss: Do Per- and polyfluoroalkyl substances matter?

Per- and poly-fluorinated substances (PFASs) with endocrine disrupting effect can efficiently transfer across the blood-follicle barrier. However, it is still controversial and attracting extensive public concern that whether PFASs can affect the human fertility potential. Therefore, we aimed to analyze the associations of women's exposure to PFASs with pregnancy loss, the relevant processes of fertilization, zygote implantation, and embryo development by using a prospective cohort study. The women undergoing in vitro fertilization-embryo transfer (IVF-ET) treatment were recruited in Beijing City (Beijing Center) and Yantai City (Yantai Center) in China during 2015-2017. A total of 305 women were recruited before the IVF-ET treatment. Twelve PFASs were measured in their serum samples collected in the day before the IVF-ET treatment, as well as in the human chorionic gonadotropin (hCG) day. The three IVF-ET outcomes were included, i.e. hCG test negative, clinical pregnancy failure (CPF), and preclinical spontaneous abortion. Nine serum PFASs had detection rate of >70% in Beijing and Yantai centers. The exposure patterns to PFASs between these two centers were overall different. For Beijing Center, we only found a positive association of perflurodecanoic acid (PFDA) with the risk of CPF [RR = 2.28 (95 %CI: 1.02-5.11)], but there is a reverse trend in Yantai Center with [RR = 0.45 (95 %CI: 0.23-0.85)]. However, the serum concentration of PFDA in Beijing Center was relatively lower than that of Yantai Center. Other significant associations of the detected PFASs with the IVF-ET outcomes, or with the relevant clinical processes, were not found. The multi-pollutant regression model of the Bayesian kernel machine regression suggested that there were no joint effects between various PFASs on the concerned outcomes. Overall, we suggest that most PFAS were not associated with early pregnancy loss at the current exposure levels. As for the PFDA, there may exist susceptibility of different populations.

Structural basis for molecular recognition of G protein-coupled estrogen receptor by selected bisphenols

Complicated ligand-dependent signaling pathways of bisphenol A (BPA) and its analogues involve not only intranuclear estrogen receptor but also membrane receptor G protein-coupled estrogen receptor (GPER). However, the structural basis for molecular recognition of GPER by the environmental chemicals remains unknown. To reveal the structural dependence of GPER recognition by bisphenols, a systematic molecular dynamics simulation study was performed for selected bisphenols with different electron hybrid orbitals and substituents on their C atoms connecting two phenol rings. BPA was used as a control, bisphenol C(BPC) as an example for a connecting C with sp² hybrid orbitals to provide more ligand rigidity, bisphenol E(BPE) and bisphenol F(BPF) for decreased steric hindrance and hydrophobicity around the connecting C, and bisphenol B(BPB) and bisphenol AF(BPAF) for increased hydrophobicity and steric hindrance. All the tested bisphenols can bind with GPER at its classic orthosteric site to obtain GPER-ligand complexes, while van der Waals interactions and direct inter-molecular electrostatic energies provide the driving forces for ligand binding. Bulky substituents and structural rigidity of the connecting C dramatically impair hydrogen bonding between GPER and the bisphenols, which results in decreased contribution of both favorable intermolecular hydrogen bonds and unfavorable polar solvation effect to complex stability of BPB and BPC since decreased number of key residues is expected. Increase in substituent lipophilicity enhances the van der Waals interactions and favorable non-polar solvation effect. The six bisphenols of high structural similarity shared two key recognition residues, Leu137^TM3 and Trp272^TM6, the latter of which was in the highly conserved CWxP motif of TM6 and has been reported as key residue for G protein-coupled receptor activation. Based on the obtained knowledge, GPER affinity and relevant toxicity of BPA alternatives can be easily predicted, and the calculated binding free energies are consistent with the available experimental observations.

Occurrence, profiles, and ecotoxicity of poly- and perfluoroalkyl substances and their alternatives in global apex predators: A critical review

Certain poly- and perfluoroalkyl substances (PFASs) exhibit significant bioaccumulation/biomagnification behaviors in ecosystems. PFASs, such as perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS) and related precursors, have elicited attention from both public and national regulatory agencies, which has resulted in worldwide restrictions on their production and use. Apex predators occupy the top trophic positions in ecosystems and are most affected by the biomagnification behavior of PFASs. Meanwhile, the long lifespans of apex predators also lead to the high body burden of PFASs. The high body burden of PFASs might be linked to adverse health effects and even pose a potential threat to their reproduction. As seen in previous reviews of PFASs, knowledge is lacking between the current stage of the PFAS body burden and related effects in apex predators. This review summarized PFAS occurrence in global apex predators, including information on the geographic distribution, levels, profiles, and tissue distribution, and discussed the trophic transfer and ecotoxicity of PFASs. In the case where legacy PFASs were restricted under international convention, the occurrence of novel PFASs, such as 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) and perfluoroethylcyclohexane sulfonate (PFECHS), in apex predators arose as an emerging issue. Future studies should develop an effective analytical method and focus on the toxicity and trophic transfer behavior of novel PFASs.

Perfluoroalkyl substances in precipitation from the Tibetan Plateau during monsoon season: Concentrations, source regions and mass fluxes

Atmospheric wet deposition is an important process for the occurrence of perfluoroalkyl substances (PFASs) in polar/remote mountain regions; however, there are limited data on PFASs in precipitation from the Tibetan Plateau (TP). Precipitation (rain from May to October 2017) was therefore collected across the TP to investigate the concentrations, composition profiles, sources, and fluxes of perfluoroalkyl acids (PFAAs). The average ∑PFAA concentrations ranged from 212.3 pg L^-1 to 547.7 pg L^-1, and perfluoroalkyl carboxylic acids (PFCAs) accounted for 87% of the measured PFAAs (mean value). Significant positive associations (p < 0.05) were found for most PFCAs in the southeast TP, indicating that they may come from similar sources. The monthly PFAA deposition flux ranged from 12.6 to 68.9 ng m^-2 month^-1, decreasing from east to west. As climate of the eastern TP is controlled mainly by the Indian monsoon, indicating that the Indian monsoon plays an important role in delivering PFAAs to the TP. PCA (principal component analysis) combined with back-trajectory analysis was used to estimate the atmospheric transport pathways, and the PSCF (potential source contribution function) model was applied to define the potential source regions of individual PFAAs. The results suggested that northeast India, Bangladesh, and southern Nepal are the potential sources of C4-C7 PFCAs; C8-C10 PFCAs are more influenced by emissions from southern Nepal and Bhutan; while the source regions of long-chain PFCAs (C11-C12) can be attributed to northern India and Pakistan. Specifically, PFOS (perfluorooctane sulfonic acid) has a local contribution from the central TP.

Branching Fraction Measurements of the Rare B_{s}^{0}→ϕμ^{+}μ^{-} and B_{s}^{0}→f_{2}^{'}(1525)μ^{+}μ^{-} Decays

The branching fraction of the rare B_{s}^{0}→ϕμ^{+}μ^{-} decay is measured using data collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to integrated luminosities of 1, 2, and 6  fb^{-1}, respectively. The branching fraction is reported in intervals of q^{2}, the square of the dimuon invariant mass. In the q^{2} region between 1.1 and 6.0  GeV^{2}/c^{4}, the measurement is found to lie 3.6 standard deviations below a standard model prediction based on a combination of light cone sum rule and lattice QCD calculations. In addition, the first observation of the rare B_{s}^{0}→f_{2}^{'}(1525)μ^{+}μ^{-} decay is reported with a statistical significance of 9 standard deviations and its branching fraction is determined.

[The prevalence rate and influencing factors of cough in children under 5 years old in Yiwu city, Zhejiang Province in 2019]

Objectives: To investigate the prevalence of cough and its influencing factors in community children under 5 years old. Methods: From October to December 2019, we selected 3 102 community children under the age of 5 from 50 natural villages/residential communities in 14 towns/streets of Yiwu, Zhejiang Province, using multi-stage random sampling method. A face-to-face and on-site questionnaire survey was conducted among child caregivers to collect demographic data and information about children's cough in the last 1 month. Multiple logistic regression model was used to analyze children's cough and the influencing factors of different cough states. Results: Multivariate logistic regression model analysis results showed that compared with 0-1 year old, dispersed, caregivers with education level below high school, families with 1 child under 5 years old, Cough risk was higher in 1-2, 2-3, 3-4 years old, nurseries, caregivers with education level of high school or above, and families with more than 2 children under 5 years old. OR (95%CI) values were 1.52(1.19-1.92), 1.65(1.29-2.10), 1.86(1.36-2.54), 2.59(1.99-3.38), 1.48(1.26-1.74) and 1.35(1.13-1.62), respectively. Further analysis of the influencing factors of different states of cough, multivariate logistic regression model analysis results showed that preschool status, the number of children under 5 years old in the family and the education level of caregivers were the influencing factors of acute, prolonged and chronic cough. Age was only an influencing factor of acute and persistent cough. Conclusions: The disease burden of cough in children under 5 years old community was heavy, and the cough was related to children's age, education level of caregivers, number of children under 5 years old in the family and childcare status.

Search for Lepton Number and Flavor Violation in K^{+} and π^{0} Decays

Searches for the lepton number violating K^{+}→π^{-}μ^{+}e^{+} decay and the lepton flavor violating K^{+}→π^{+}μ^{-}e^{+} and π^{0}→μ^{-}e^{+} decays are reported using data collected by the NA62 experiment at CERN in 2017-2018. No evidence for these decays is found and upper limits of the branching ratios are obtained at 90% confidence level: B(K^{+}→π^{-}μ^{+}e^{+})<4.2×10^{-11}, B(K^{+}→π^{+}μ^{-}e^{+})<6.6×10^{-11} and B(π^{0}→μ^{-}e^{+})<3.2×10^{-10}. These results improve by 1 order of magnitude over previous results for these decay modes.

Observation of the Mass Difference between Neutral Charm-Meson Eigenstates

A measurement of mixing and CP violation in neutral charm mesons is performed using data reconstructed in proton-proton collisions collected by the LHCb experiment from 2016 to 2018, corresponding to an integrated luminosity of 5.4  fb^{-1}. A total of 30.6 million D^{0}→K_{S}^{0}π^{+}π^{-} decays are analyzed using a method optimized for the measurement of the mass difference between neutral charm-meson eigenstates. Allowing for CP violation in mixing and in the interference between mixing and decay, the mass and decay-width differences are measured to be x_{CP}=[3.97±0.46(stat)±0.29(syst)]×10^{-3} and y_{CP}=[4.59±1.20(stat)±0.85(syst)]×10^{-3}, respectively. The CP-violating parameters are measured as Δx=[-0.27±0.18(stat)±0.01(syst)]×10^{-3} and Δy=[0.20±0.36(stat)±0.13(syst)]×10^{-3}. This is the first observation of a nonzero mass difference in the D^{0} meson system, with a significance exceeding seven standard deviations. The data are consistent with CP symmetry and improve existing constraints on the associated parameters.

The safety and efficacy of transarterial chemoembolisation with bleomycin for hepatocellular carcinoma unresponsive to doxorubicin: a prospective single-centre study

AIM

To investigate the safety and efficacy of transarterial chemoembolisation (TACE) with bleomycin for hepatocellular carcinoma (HCC) unresponsive to doxorubicin.

MATERIALS AND METHODS

A randomised controlled trial was undertaken of HCC patients resistant to TACE with doxorubicin to assess the survival benefits of the experimental group (TACE with bleomycin) compared with the control group (TACE with doxorubicin). One hundred and seventy patients were allocated randomly between December 2015 and December 2017, and 80 patients of each group were analysed. The modified response evaluation criteria in solid tumours (mRECIST) was used to evaluated the tumour response every 4-6 weeks. The primary endpoint was median progression-free survival (mPFS) and median overall survival (mOS). Safety was assessed by post-procedure complications.

RESULTS

The study was completed in October 2018. Objective response rate (ORR) of the experimental group was 27.5% (22/80), mPFS and mOS was 5.8 and 8.1 months. ORR of the control group was 7.5% (6/80), mPFS and mOS was 2.9 and 4 months. The ORR were significantly different between two groups (χ² = 0.348, p<0.05). The differences of mPFS and mOS between the two groups were statistically significant (χ² = 2.865, p<0.05 and χ² = 0.926, p<0.05, respectively). There were no significant difference in post-procedure complications (p>0.05) and no major complications occurred.

CONCLUSION

It is suggested that TACE with bleomycin is a safe and effective method for HCC and bleomycin can be a second-line chemotherapeutic agent for the HCC patients unresponsive to TACE with doxorubicin.

Observation of New Resonances Decaying to J/ψK^{+} and J/ψϕ

The first observation of exotic states with a new quark content cc[over ¯]us[over ¯] decaying to the J/ψK^{+} final state is reported with high significance from an amplitude analysis of the B^{+}→J/ψϕK^{+} decay. The analysis is carried out using proton-proton collision data corresponding to a total integrated luminosity of 9  fb^{-1} collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV. The most significant state, Z_{cs}(4000)^{+}, has a mass of 4003±6_{-14}^{+4}  MeV, a width of 131±15±26  MeV, and spin parity J^{P}=1^{+}, where the quoted uncertainties are statistical and systematic, respectively. A new 1^{+}  X(4685) state decaying to the J/ψϕ final state is also observed with high significance. In addition, the four previously reported J/ψϕ states are confirmed and two more exotic states, Z_{cs}(4220)^{+} and X(4630), are observed with significance exceeding 5 standard deviations.

Erratum: Azimuthal Anisotropy of K_{S}^{0} and Λ+Λ[over ¯] Production at Midrapidity from Au+Au Collisions at sqrt[s]_{NN}=130 GeV [Phys. Rev. Lett. 89, 132301 (2002)]

This corrects the article DOI: 10.1103/PhysRevLett.89.132301.

Erratum: Azimuthal Anisotropy at the Relativistic Heavy Ion Collider: The First and Fourth Harmonics [Phys. Rev. Lett. 92, 062301 (2004)]

This corrects the article DOI: 10.1103/PhysRevLett.92.062301.

O-045 Synthetic human embryo-like structures: a new paradigm for human embryology

Early human development remains mysterious and very difficult to study. Recent advances in mammalian embryology, stem cell biology, organoid technology, and bioengineering have contributed to a significant interest in bottom-up, synthetic stem cell-derived models of human development (or embryoids). The controllability and reproducibility of human embryoids coupled with the ease of genetically modifying stem cell lines, the ability to manipulate culture conditions and the simplicity of live imaging make them robust and attractive systems to disentangle cellular behaviors and signaling interactions that drive human embryogenesis. In this talk, I will describe our effort in using human pluripotent stem cells (hPSCs) to develop tractable experimental models of the peri-implantation embryonic development and neurulation. The peri-implantation human embryoids developed by us recapitulate key early post-implantation developmental landmarks successively, including pro-amniotic cavity formation, amniotic ectoderm-epiblast patterning, primordial germ cell specification, and development of the primitive streak with controlled anteroposterior polarity. I will further discuss an hPSC-based neuroectoderm patterning model to recapitulate the formation of the neural plate and another patterned neural tube model with fully defined anterior-posterior and dorsal-ventral axes.

Long-Range Transport, Trophic Transfer, and Ecological Risks of Organophosphate Esters in Remote Areas

Organophosphate esters (OPEs) have been a focus in the field of environmental science due to their large volume production, wide range of applications, ubiquitous occurrence, potential bioaccumulation, and worrisome ecological and health risks. Varied physicochemical properties among OPE analogues represent an outstanding scientific challenge in studying the environmental fate of OPEs in recent years. There is an increasing number of studies focusing on the long-range transport, trophic transfer, and ecological risks of OPEs. Therefore, it is necessary to conclude the OPE pollution status on a global scale, especially in the remote areas with vulnerable and fragile ecosystems. The present review links together the source, fate, and environmental behavior of OPEs in remote areas, integrates the occurrence and profile data, summarizes their bioaccumulation, trophic transfer, and ecological risks, and finally points out the predominant pollution burden of OPEs among organic pollutants in remote areas. Given the relatively high contamination level and bioaccumulation/biomagnification behavior of OPEs, in combination with the sensitivity of endemic species in remote areas, more attention should be paid to the potential ecological risks of OPEs.

Sonographic findings of immunoglobulin G4-related sialadenitis and differences from Sjögren's syndrome

OBJECTIVE

To evaluate ultrasonic features of the major salivary glands in patients with immunoglobulin G₄-related sialadenitis (IgG₄-RS) and to explore the differences between IgG₄-RS and Sjögren's syndrome (SS).

METHOD

We conducted the study in 150 patients with IgG₄-RS and 100 patients with SS. Ultrasonographic variables of the static images of major salivary glands were analysed. An experienced radiologist scored the confidence rating regarding the presence of the characteristic imaging findings using a five-grade rating system. Ultrasonography scores between IgG₄-RS and SS were compared.

RESULTS

The major salivary glands were significantly larger in patients with IgG₄-RS than in the SS group. The main features of ultrasonography of the salivary glands in IgG₄-RS were various hypoechoic lesions and increased colour Doppler signalling. In contrast, the major salivary glands in SS exhibited hyperechoic lines and/or spots and obscuration of the gland configuration. The scores of the summarized sonographic characteristics also showed statistically significant differences between the IgG₄-RS and SS groups.

CONCLUSION

This study revealed different ultrasonic features of the major salivary glands in patients with IgG₄-RS and SS. The scored sonographic features were helpful in differentiating IgG₄-RS from SS. Consequently, we suggest that ultrasonography of major salivary glands could be a useful imaging procedure in the evaluation of patients suspected of having IgG₄-RS.

SepPCNET: Deeping Learning on a 3D Surface Electrostatic Potential Point Cloud for Enhanced Toxicity Classification and Its Application to Suspected Environmental Estrogens

Deep learning (DL) offers an unprecedented opportunity to revolutionize the landscape of toxicity prediction based on quantitative structure-activity relationship (QSAR) studies in the big data era. However, the structural description in the reported DL-QSAR models is still restricted to the two-dimensional level. Inspired by point clouds, a type of geometric data structure, a novel three-dimensional (3D) molecular surface point cloud with electrostatic potential (SepPC) was proposed to describe chemical structures. Each surface point of a chemical is assigned its 3D coordinate and molecular electrostatic potential. A novel DL architecture SepPCNET was then introduced to directly consume unordered SepPC data for toxicity classification. The SepPCNET model was trained on 1317 chemicals tested in a battery of 18 estrogen receptor-related assays of the ToxCast program. The obtained model recognized the active and inactive chemicals at accuracies of 82.8 and 88.9%, respectively, with a total accuracy of 88.3% on the internal test set and 92.5% on the external test set, which outperformed other up-to-date machine learning models and succeeded in recognizing the difference in the activity of isomers. Additional insights into the toxicity mechanism were also gained by visualizing critical points and extracting data-driven point features of active chemicals.

Associations between WNT signaling pathway-related gene polymorphisms and risks of osteoporosis development in Chinese postmenopausal women: a case-control study

BACKGROUND

The WNT signaling pathway is involved in the regulation of bone homeostasis, and the effect of WNT signaling pathway-related gene (WNT16 and LRP5) polymorphisms on osteoporosis risk among Chinese postmenopausal women is still unknown. Hence, we performed a case-control study to assess the association of WNT signaling pathway-related gene polymorphisms and osteoporosis risk.

METHODS

A total of 1026 women (515 osteoporosis patients and 511 controls) of postmenopausal age who were randomly sampled from Xi'an 630 Hospital (Shaanxi Province, China) were involved in this study. Seven genetic polymorphisms in WNT16 (rs3779381, rs3801387, rs917727 and rs7776725) and LRP5 (rs2291467, rs11228240 and rs12272917) were selected and genotyped using the Agena MassARRAY iPLEX system. The association of the genetic polymorphisms and osteoporosis risk was assessed by odds ratios and 95% confidence intervals. The multifactor dimensionality reduction (MDR) method was conducted to analyze single nucleotide polymorphism (SNP)-SNP interaction.

RESULTS

We found that LRP5 polymorphisms (rs2291467, rs11228240 and rs12272917) were significantly associated with a decreased risk of osteoporosis in homozygote, recessive and additive models (p < 0.05). Stratification analysis showed that LRP5 polymorphisms (rs2291467, rs11228240 and rs12272917) significantly decreased the osteoporosis risk in the subgroup of body mass index (BMI) ≤ 24 (p < 0.05) and that individuals carrying a heterozygote genotype of WNT16 polymorphisms (rs3779381, rs3801387, rs917727 and rs7776725) had a higher osteoporosis risk in the subgroup of BMI > 24 (p < 0.05). Two haplotypes (haplotype 1: rs3779381, rs3801387, rs917727 and rs7776725; haplotype 2: rs2291467 and rs11228240) were observed, yet only T_rs2291467T_rs11228240 and C_rs2291467C_rs11228240 had a strong association with a decreased risk of osteoporosis (p < 0.05). Additionally, MDR analysis revealed that LRP5 rs2291467 was the best model in single-locus MDR analysis. A seven-locus model including rs3779381-AG, rs7776725-TC, rs3801387-GA and rs917727-TC in WNT16 and rs11228240-CC, rs12272917-TC and rs2291467-CC in LRP5 was the best model in multiple-loci MDR analysis (p < 0.001). These two best models were the most significantly associated with osteoporosis risk.

CONCLUSIONS

Our findings suggested that WNT16 and LRP5 genetic polymorphisms are associated with osteoporosis risk among Chinese postmenopausal women.

Increased Vδ1γδT cells predominantly contributed to IL-17 production in the development of adult human post-infectious irritable bowel syndrome

Background

γδT cells play an important role in the mucosa inflammation and immunity-associated disorders. Our previous study reported that γδ T cells producing IL-17 were involved in the pathogenesis of post-infectious irritable bowel syndrome (PI-IBS). However, their subset characteristic profile in this kind of disease remains unclear. Thus the current study’s aim is to investigate the functionally predominant subset and its role in PI-IBS.

Methods

The total T cells were collected from the peripheral blood of patients with PI-IBS. The peripheral proportion of Vδ1 and Vδ2 subset was detected by FACS after stained with anti δ1-PE and anti δ2-APC. The local colonic proportion of this two subsets were measured under laser confocal fluorescence microscope. Vδ1 γδ T cells were enriched from the total peripheral T cells by minoantibody-immuno-microbeads (MACS) method and cultured, functionally evaluated by CCK-8 assay (proliferation), CD69/CD62L molecules expression assay (activation) and ELISA (IL-17 production) respectively.

Results

1. Vδ1 γδ T cells significantly increased while Vδ2 γδ T cells remained unchanged in both the peripheral blood and local colonic tissue from PI-IBS patients (p < 0.05). 2. When cultured in vitro, the Vδ1 γδ T cells remarkably proliferated, activated and produced IL-17 (p < 0.05).

Conclusions

Our results suggest that Vδ1 γδ T cells was the predominant γδ T cells subset in both peripheral and intestinal tissue, and was the major IL-17 producing γδ T cells in PI-IBS.

Toxicity of Tetrabromobisphenol A and Its Derivative in the Mouse Liver Following Oral Exposure at Environmentally Relevant Levels

As typical brominated flame retardants (BFRs), tetrabromobisphenol A (TBBPA) and its derivative TBBPA-bis(2,3-dibromopropyl ether) (TBBPA-BDBPE) are ubiquitous in various environmental compartments. However, the potential health risk posed by these compounds, especially at environmentally relevant levels, remains unclear. In this study, using adult male mice, we investigated the toxicity of orally administered TBBPA and TBBPA-BDBPE at an environmentally relevant dose (57 nmol/kg body weight). After a single exposure and daily exposure, we assessed lipid metabolism homeostasis, the transcriptome, and immune cell components in the liver. We found that the single exposure to TBBPA or TBBPA-BDBPE alone increased the number of hepatic macrophages, induced alterations in the levels of lipids, including triacylglycerol and free fatty acids, and caused transcriptome perturbation. The results from the daily administration groups showed that TBBPA and TBBPA-BDBPE both significantly increased the triacylglycerol content; however, the elevation of hepatic macrophages was observed only in the TBBPA-BDBPE treatment group. This study confirmed that environmentally relevant levels of TBBPA and TBBPA-BDBPE are toxic to the liver. Our findings revealed that dysfunction of the liver is a health concern, following exposure to BFRs, even at very low concentrations. The chronic effects induced by TBBPA and its derivatives should be further investigated.

Association of clinical factors and recent anticancer therapy with COVID-19 severity among patients with cancer: a report from the COVID-19 and Cancer Consortium

BACKGROUND

Patients with cancer may be at high risk of adverse outcomes from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. We analyzed a cohort of patients with cancer and coronavirus 2019 (COVID-19) reported to the COVID-19 and Cancer Consortium (CCC19) to identify prognostic clinical factors, including laboratory measurements and anticancer therapies.

PATIENTS AND METHODS

Patients with active or historical cancer and a laboratory-confirmed SARS-CoV-2 diagnosis recorded between 17 March and 18 November 2020 were included. The primary outcome was COVID-19 severity measured on an ordinal scale (uncomplicated, hospitalized, admitted to intensive care unit, mechanically ventilated, died within 30 days). Multivariable regression models included demographics, cancer status, anticancer therapy and timing, COVID-19-directed therapies, and laboratory measurements (among hospitalized patients).

RESULTS

A total of 4966 patients were included (median age 66 years, 51% female, 50% non-Hispanic white); 2872 (58%) were hospitalized and 695 (14%) died; 61% had cancer that was present, diagnosed, or treated within the year prior to COVID-19 diagnosis. Older age, male sex, obesity, cardiovascular and pulmonary comorbidities, renal disease, diabetes mellitus, non-Hispanic black race, Hispanic ethnicity, worse Eastern Cooperative Oncology Group performance status, recent cytotoxic chemotherapy, and hematologic malignancy were associated with higher COVID-19 severity. Among hospitalized patients, low or high absolute lymphocyte count; high absolute neutrophil count; low platelet count; abnormal creatinine; troponin; lactate dehydrogenase; and C-reactive protein were associated with higher COVID-19 severity. Patients diagnosed early in the COVID-19 pandemic (January-April 2020) had worse outcomes than those diagnosed later. Specific anticancer therapies (e.g. R-CHOP, platinum combined with etoposide, and DNA methyltransferase inhibitors) were associated with high 30-day all-cause mortality.

CONCLUSIONS

Clinical factors (e.g. older age, hematological malignancy, recent chemotherapy) and laboratory measurements were associated with poor outcomes among patients with cancer and COVID-19. Although further studies are needed, caution may be required in utilizing particular anticancer therapies.

CLINICAL TRIAL IDENTIFIER

NCT04354701.

A compact electron beam ion trap in support of high-temperature plasma diagnostics based on conduction-cooled superconducting coils

Spectroscopic diagnostics of future fusion reactor plasmas require information on impurity line emissions, especially for relevant high-Z metal elements (e.g., tungsten). These materials will be widely used as plasma facing components for their high heat tolerance and low sputtering yield. Based on an electron beam ion trap, a compact impurity spectra platform is developed to mimic the high-temperature environment of a fusion reactor. The proposed platform can deliver a focused e-beam at energies over 30 keV using a confining magnetic field of ∼1.0 T generated by two superconducting coils (NbTi). Cooled by a closed-loop cryocooler, the coils can avoid the usage of a complicated cryogenic system involving the handling of liquid helium. For spectroscopic studies of highly charged ions, a spherically curved crystal spectrometer is proposed to measure a wavelength range around 2-4 Å covering the typical wavelength range expected to be emitted by metal ions in a fusion plasma. This paper reports the design and development progress of the platform.

Katabatic Wind and Sea-Ice Dynamics Drive Isotopic Variations of Total Gaseous Mercury on the Antarctic Coast

Clarifying the sources and fates of atmospheric mercury (Hg) in the Antarctic is crucial to understand the global Hg circulation and its impacts on the fragile ecosystem of the Antarctic. Herein, the annual variations in the isotopic compositions of total gaseous Hg (TGM), with 5-22 days of sampling duration for each sample, were presented for the first time to provide isotopic evidence of the sources and environmental processes of gaseous Hg around the Chinese Great Wall Station (GWS) in the western Antarctic. Different from the Arctic tundra and lower latitude areas in the northern hemisphere, positive δ²⁰²Hg (0.58 ± 0.21‰, mean ± 1SD) and negative Δ¹⁹⁹Hg (-0.30 ± 0.10‰, mean ± 1SD) in TGM at the GWS indicated little impact from the vegetation-air exchange in the Antarctic. Correlations among TGM Δ¹⁹⁹Hg, air temperature, and ozone concentrations suggested that enhanced katabatic wind that transported inland air masses to the continental margin elevated TGM Δ¹⁹⁹Hg in the austral winter, while the surrounding marine surface emissions controlled by sea-ice dynamics lowered TGM Δ¹⁹⁹Hg in the austral summer. The oxidation of Hg(0) might elevate Δ¹⁹⁹Hg in TGM during atmospheric Hg depletion events but have little impact on the seasonal variations of atmospheric Hg isotopes. The presented atmospheric Hg isotopes were essential to identify the transport and transformation of atmospheric Hg and further understand Hg cycling in the Antarctic.

Real-time signal processing system based on FPGA for motional Stark effect diagnostic on EAST

The plasma current density profile plays a key role in the development of a high poloidal beta scenario, which is essential for long-pulse and high-performance plasma operation on a tokamak. Based on the polarimetry technique, a Motional Stark Effect (MSE) diagnostic has been built on the Experimental Advanced Superconducting Tokamak. To be prepared for real-time (RT) feedback control of the plasma current density profile in the future, a RT signal processing system has been developed. The RT signal processing system is composed of three functional modules: analog-to-digital conversion (ADC) module, polarization information extraction module, and digital-to-analog conversion (DAC) module. The final objective of this system is to acquire the polarization information of the MSE. Based on the field-programmable gate array unit, fast Fourier transformation is adopted to process the Photoelastic Modulator (PEM) digital signal, which was converted from a PEM signal via the ADC module. By means of frequency spectrum separation, the components around double modulating frequencies are restored through inverse fast Fourier transformation. Furthermore, the two amplitudes of their corresponding components can be obtained through a digital harmonic analyzer technique. Afterward, the ratio of the two amplitudes is calculated by arc tangent so that the polarization angle is obtained. Finally, the information of this polarization angle is converted into a voltage signal by the DAC module and then output in RT. The test results based on the RT signal processing system are in good agreement with those based on the phase lock-in amplifiers. The working cycle of this system is shorter than 10 ms, which meets the requirements of the MSE diagnostic as a RT controller. The algorithm of RT signal processing and the relevant technology applied for building this system are presented in the main body of this paper in detail.

Angular Analysis of the B^{+}→K^{*+}μ^{+}μ^{-} Decay

We present an angular analysis of the B^{+}→K^{*+}(→K_{S}^{0}π^{+})μ^{+}μ^{-} decay using 9  fb^{-1} of pp collision data collected with the LHCb experiment. For the first time, the full set of CP-averaged angular observables is measured in intervals of the dimuon invariant mass squared. Local deviations from standard model predictions are observed, similar to those in previous LHCb analyses of the isospin-partner B^{0}→K^{*0}μ^{+}μ^{-} decay. The global tension is dependent on which effective couplings are considered and on the choice of theory nuisance parameters.

Hsa_circRNA_101036 acts as tumor-suppressor in oral squamous cell carcinoma cells via inducing endoplasmic reticulum stress

OBJECTIVE

Endoplasmic reticulum (ER) stress has an effect on cancer cell proliferation and survival. TMTC1 has been reported to be involved in cell proliferation and inflammation, and development of ER. Hsa_circRNA_101036 is an exon circRNA formed by splicing of TMTC1 mRNA precursor. This study intends to explore the effect of hsa_circRNA_101036 on the malignant behavior of oral squamous cell carcinoma through endoplasmic reticulum stress.

MATERIALS AND METHODS

We firstly evaluated the levels of Hsa_circRNA_101036 in human oral mucous fibroblasts (hOMF), and in several OSCC cell lines, including FaDu, OECM1, SAS, HSC3. Then, we studied the effects of overexpression of Hsa_circRNA_101036 on the cell proliferation, apoptosis, invasion, migration, and cytokine release in OSCC cells. Finally, we evaluated the levels of CHOP that are critical in ER and the ROS levels in OSCC cells.

RESULTS

We found that compared with hOMF, a significantly lower mRNA expression of Hsa_circRNA_101036 was found in OECM1 and HSC3 cells. In OECM1 and HSC3 cells, with overexpression of Hsa_circRNA_101036, a significant decrease in cell proliferation, apoptosis, invasion, migration, and cytokine release was found. A significantly increased ROS, as well as increased protein level of CHOP, P38 and Bcl-2, was found in cells with Hsa_circRNA_101036 overexpression.

CONCLUSIONS

This study indicated that Hsa_circRNA_101036 may acts as a tumor suppressor in OSCC via regulating the ER in cancer cells.

Comparing the efficacy of endovascular treatment for iliac vein compression syndrome with or without acute deep venous thrombosis: A single-center retrospective study

BACKGROUND

To compare the efficacy of endovascular treatment for iliac vein compression syndrome (IVCS) with or without acute deep venous thrombosis of lower extremity.

METHODS

This study retrospectively analyzed the clinical data of 300 IVCS patients, who received endovascular treatment between January 2013 and December 2017. According to whether IVCS was complicated by deep venous thrombosis or not, these patients were divided into non-thrombotic iliac vein lesion group (NIVL group, n = 127) and post-thrombotic iliac vein lesion group (PIVL group, n = 173). After endovascular treatment, all patients were followed up to assess the symptoms improvement and to evaluate the patency of iliac vein.

RESULTS

The technical success rate was 98% (294/300), and percutaneous transluminal angioplasty with stenting was adopted in 294 cases. The incidence of perioperative complications was 36.33% (109/300), but no severe complications occurred. During a mean follow-up of 22.3 months (range 6-30 months), 9(6.82%, 9/132) patients in PIVL group had recurrence of deep venous thrombosis, but nobody had deep venous thrombosis and varicose veins recurrence in NIVL group. The effective rate of endovascular treatment in NIVL group and PIVL group was 96.88% and 90.15% (P = 0.050), while the cumulative primary patency of iliac vein in NIVL group was significantly higher than that in PIVL group (P = 0.008).

CONCLUSIONS

The endovascular treatment is an effective, feasible, safe method for treating IVCS. There is no difference in the efficacy of IVCS patients with or without deep venous thrombosis, but the medium and long-term patency of patients with deep venous thrombosis is lower than that in patients without deep venous thrombosis.

Development and preliminary test of a space-resolved vacuum-ultraviolet spectroscopy in EAST

The impurity radiation from the divertor region of the EAST tokamak is dominantly in the wavelength range of vacuum ultraviolet (VUV) due to the elevated edge electron temperature. A space-resolved VUV spectroscopy is developed to measure impurity radiation in the divertor region. An eagle-type VUV spectrometer with a focal length of 1 m is adopted in this system, equipped with a spherical grating and a charged-coupled device (CCD) detector. The performance of the VUV spectrometer is preliminarily tested on a synchrotron radiation facility. The wavelength calibration is conducted near 65 nm. It is found that the wavelength range observed by the CCD detector is about 11.07 nm around the central wavelength of about 65 nm. With a linear dispersion of 0.0053 nm/pixel, it is possible to measure the ion temperature lower than 20 eV at the edge region by analyzing the Doppler broadening of a carbon line. These test results show that the performance of the VUV spectrometer is capable of measuring divertor radiation and analyzing the ion temperature of edge impurity ions.

Observation of a New Excited D_{s}^{+} Meson in B^{0}→D^{-}D^{+}K^{+}π^{-} Decays

Using pp collision data corresponding to an integrated luminosity of 5.4  fb^{-1} collected with the LHCb detector at a center-of-mass energy of 13 TeV, the B^{0}→D^{-}D^{+}K^{+}π^{-} decay is studied. A new excited D_{s}^{+} meson is observed decaying into the D^{+}K^{+}π^{-} final state with large statistical significance. The pole mass and width, and the spin parity of the new state are measured with an amplitude analysis to be m_{R}=2591±6±7  MeV, Γ_{R}=89±16±12  MeV, and J^{P}=0^{-}, where the first uncertainty is statistical and the second systematic. Fit fractions for all components in the amplitude analysis are also reported. The new resonance, denoted as D_{s0}(2590)^{+}, is a strong candidate to be the D_{s}(2^{1}S_{0})^{+} state, the radial excitation of the pseudoscalar ground-state D_{s}^{+} meson.

Circular RNA circDENND4C facilitates proliferation, migration and glycolysis of colorectal cancer cells through miR-760/GLUT1 axis

OBJECTIVE

Colorectal cancer is a common malignant tumor of the digestive tract, and its incidence is closely related to lifestyle inheritance and colorectal adenoma. Circular RNA (circRNA) has been proved to participate in the progression of colorectal cancer cells. Our study aimed to investigate the function and the underlying mechanism of circRNA circDENND4C in colorectal cancer cells.

PATIENTS AND METHODS

The expression of circDENND4C, glucose transporter 1 (GLUT1), and miR-760 was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Western blot was used to measure the protein levels of GLUT1, the proliferation-related protein (Cyclin D1) and matrix metallopeptidase 9 (MMP-9). Cell Counting Kit-8 (CCK-8) assay and transwell assay were performed to evaluate cell proliferation and migration. The glucose uptake and lactate production were detected by the corresponding kits. The targets between circDENND4C and miR-760 and miR-760 and GLUT1 were predicted by starBase 3.0 and TargetScan, and then confirmed by Dual-Luciferase reporter assay. Animal experiment revealed the effect of circDENND4C on colorectal cancer cells in vivo.

RESULTS

The expression of circDENND4C and GLUT1 was upregulated in colorectal cancer tissues and cells. Functionally, the knockdown of circDENND4C suppressed proliferation, migration, and glycolysis of colorectal cancer cells. Similarly, silence of GLUT1 also inhibited cell proliferation, migration, and glycolysis. Notably, the overexpression of GLUT1 reversed the functional effects of circDENND4C knockdown on colorectal cancer cells. More importantly, miR-760 acted as a direct target of circDENND4C, and miR-760 could bind to GLUT1, and circDENND4C regulated GLUT1 by sponging miR-760. Finally, circDENND4C knockdown decreased the growth of colorectal cancer cells in vivo.

CONCLUSIONS

CircRNA circDENND4C accelerated proliferation, migration, and glycolysis of colorectal cancer cells through regulating GLUT1 by sponging miR-760.

Observation of Multiplicity Dependent Prompt χ_{c1}(3872) and ψ(2S) Production in pp Collisions

The production of χ_{c1}(3872) and ψ(2S) hadrons is studied as a function of charged particle multiplicity in pp collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 2  fb^{-1}. For both states, the fraction that is produced promptly at the collision vertex is found to decrease as charged particle multiplicity increases. The ratio of χ_{c1}(3872) to ψ(2S) cross sections for promptly produced particles is also found to decrease with multiplicity, while no significant dependence on multiplicity is observed for the equivalent ratio of particles produced away from the collision vertex in b-hadron decays. This behavior is consistent with a calculation that models the χ_{c1}(3872) structure as a compact tetraquark. Comparisons with model calculations and implications for the binding energy of the χ_{c1}(3872) state are discussed.

Measurement of CP Violation in the Decay B^{+}→K^{+}π^{0}

A measurement of CP violation in the decay B^{+}→K^{+}π^{0} is reported using data corresponding to an integrated luminosity of 5.4  fb^{-1} collected with the LHCb experiment at a center-of-mass energy of sqrt[s]=13  TeV. The CP asymmetry is measured to be 0.025±0.015±0.006±0.003, where the uncertainties are statistical, systematic, and due to an external input. This is the most precise measurement of this quantity. It confirms and significantly enhances the observed anomalous difference between the direct CP asymmetries of the B^{0}→K^{+}π^{-} and B^{+}→K^{+}π^{0} decays, known as the Kπ puzzle.

First Observation of the Decay B_{s}^{0}→K^{-}μ^{+}ν_{μ} and a Measurement of |V_{ub}|/|V_{cb}|

The first observation of the suppressed semileptonic B_{s}^{0}→K^{-}μ^{+}ν_{μ} decay is reported. Using a data sample recorded in pp collisions in 2012 with the LHCb detector, corresponding to an integrated luminosity of 2  fb^{-1}, the branching fraction B(B_{s}^{0}→K^{-}μ^{+}ν_{μ}) is measured to be [1.06±0.05(stat)±0.08(syst)]×10^{-4}, where the first uncertainty is statistical and the second one represents the combined systematic uncertainties. The decay B_{s}^{0}→D_{s}^{-}μ^{+}ν_{μ}, where D_{s}^{-} is reconstructed in the final state K^{+}K^{-}π^{-}, is used as a normalization channel to minimize the experimental systematic uncertainty. Theoretical calculations on the form factors of the B_{s}^{0}→K^{-} and B_{s}^{0}→D_{s}^{-} transitions are employed to determine the ratio of the Cabibbo-Kobayashi-Maskawa matrix elements |V_{ub}|/|V_{cb}| at low and high B_{s}^{0}→K^{-} momentum transfer.

Long-Term Investigation of the Temporal Trends and Gas/Particle Partitioning of Short- and Medium-Chain Chlorinated Paraffins in Ambient Air of King George Island, Antarctica

The presence of anthropogenically emitted chlorinated paraffins (CPs) has been reported in the pristine regions, providing evidence of their long-range transport. This study comprehensively analyzed the short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in both gas and particle phases at King George Island, West Antarctica (the Chinese Great Wall Station), from 2014 to 2018. The atmospheric levels of CPs ranged between 71.4 and 4230 pg/m³, with an increasing temporal trend during the sampling time. Three different models (J-P model, H-B model, and L-M-Y model) were built to estimate the progress of gas/particle partitioning of CPs at the measurement site. Furthermore, we compared the measured data of the gas/particle partitioning with the data estimated using three different models. We found that the steady-state model (L-M-Y model) was more suitable for investigating the gas/particle partitioning of CPs instead of equilibrium state models (J-P model and H-B model). The result indicated that steady-state approximation rather than the equilibrium state represents the most predominant contribution to the transport of CPs to the Antarctic region. The steady-state further made it conducive to sustaining the levels of CPs for a more extended period in the atmosphere of West Antarctica.

Long-range atmospheric transport and alpine condensation of short-chain chlorinated paraffins on the southeastern Tibetan Plateau

Pristine alpine regions are ideal regions for investigating the long-range atmospheric transport and cold trapping effects of short chain chlorinated paraffins (SCCPs). The concentrations and alpine condensation of SCCPs were investigated in lichen samples collected from the southeastern Tibetan Plateau. The concentrations of SCCPs ranged from 3098 to 6999 ng/g lipid weight (lw) and appeared to have an increasing trend with altitude. For congeners, C₁₀ dominated among all the congener groups. The different environmental behavior for different congener groups was closely related to their octanol-air partition coefficient (K_oa). C₁₀ congeners showed an increasing trend with altitude, whereas C₁₃ congeners were negatively correlated with altitude. Volumetric bioconcentration factors (BCF) of SCCPs reached 8.71 in lichens, which were higher than other semivolatile organic compounds (SVOCs) such as organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and hexabromocyclododecane (HBCD). These results suggested that SCCPs were prone to accumulate in the lichen from the air and provided evidence for the role of lichens as a suitable atmospheric indicator in the Tibetan Plateau.