Displaying publications 41 - 60 of 107 in total

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  1. Jiamsakul A, Yunihastuti E, Van Nguyen K, Merati TP, Do CD, Ditangco R, et al.
    HIV Med, 2018 Apr 23.
    PMID: 29683253 DOI: 10.1111/hiv.12621
  2. Joshi K, Boettiger D, Kerr S, Nishijima T, Van Nguyen K, Ly PS, et al.
    Pharmacoepidemiol Drug Saf, 2018 Nov;27(11):1209-1216.
    PMID: 30246898 DOI: 10.1002/pds.4657
    PURPOSE: Renal disease is common among people living with human immunodeficiency virus (HIV). However, there is limited information on the incidence and risk factors associated with renal dysfunction among this population in Asia.

    METHODS: We used data from the TREAT Asia HIV Observational Database. Patients were included if they started antiretroviral therapy during or after 2003, had a serum creatinine measurement at antiretroviral therapy initiation (baseline), and had at least 2 follow-up creatinine measurements taken ≥3 months apart. Patients with a baseline estimated glomerular filtration rate (eGFR) ≤60 mL/min/1.73 m2 were excluded. Chronic kidney disease was defined as 2 consecutive eGFR values ≤60 mL/min/1.73 m2 taken ≥3 months apart. Generalized estimating equations were used to identify factors associated with eGFR change. Competing risk regression adjusted for study site, age and sex, and cumulative incidence plots were used to evaluate factors associated with chronic kidney disease (CKD).

    RESULTS: Of 2547 patients eligible for this analysis, tenofovir was being used by 703 (27.6%) at baseline. Tenofovir use, high baseline eGFR, advanced HIV disease stage, and low nadir CD4 were associated with a decrease in eGFR during follow-up. Chronic kidney disease occurred at a rate of 3.4 per 1000 patient/years. Factors associated with CKD were tenofovir use, old age, low baseline eGFR, low nadir CD4, and protease inhibitor use.

    CONCLUSIONS: There is an urgent need to enhance renal monitoring and management capacity among at-risk groups in Asia and improve access to less nephrotoxic antiretrovirals.

  3. Jiamsakul A, Kerr SJ, Kiertiburanakul S, Azwa I, Zhang F, Chaiwarith R, et al.
    AIDS Care, 2018 12;30(12):1560-1566.
    PMID: 30021450 DOI: 10.1080/09540121.2018.1499859
    Missed clinic visits can lead to poorer treatment outcomes in HIV-infected patients. Suboptimal antiretroviral therapy (ART) adherence has been linked to subsequent missed visits. Knowing the determinants of missed visits in Asian patients will allow for appropriate counselling and intervention strategies to ensure continuous engagement in care. A missed visit was defined as having no assessments within six months. Repeated measures logistic regression was used to analyse factors associated with missed visits. A total of 7100 patients were included from 12 countries in Asia with 2676 (37.7%) having at least one missed visit. Patients with early suboptimal self-reported adherence <95% were more likely to have a missed visit compared to those with adherence ≥95% (OR = 2.55, 95% CI(1.81-3.61)). Other factors associated with having a missed visit were homosexual (OR = 1.45, 95%CI(1.27-1.66)) and other modes of HIV exposure (OR = 1.48, 95%CI(1.27-1.74)) compared to heterosexual exposure; using PI-based (OR = 1.33, 95%CI(1.15-1.53) and other ART combinations (OR = 1.79, 95%CI(1.39-2.32)) compared to NRTI+NNRTI combinations; and being hepatitis C co-infected (OR = 1.27, 95%CI(1.06-1.52)). Patients aged >30 years (31-40 years OR = 0.81, 95%CI(0.73-0.89); 41-50 years OR = 0.73, 95%CI(0.64-0.83); and >50 years OR = 0.77, 95%CI(0.64-0.93)); female sex (OR = 0.81, 95%CI(0.72-0.90)); and being from upper middle (OR = 0.78, 95%CI(0.70-0.80)) or high-income countries (OR = 0.42, 95%CI(0.35-0.51)), were less likely to have missed visits. Almost 40% of our patients had a missed clinic visit. Early ART adherence was an indicator of subsequent clinic visits. Intensive counselling and adherence support should be provided at ART initiation in order to optimise long-term clinic attendance and maximise treatment outcomes.
  4. Ngoh CLY, Goh GHS, Wong WK
    Med J Malaysia, 2019 02;74(1):97-98.
    PMID: 30846674
    Thymoma is a rare mediastinal tumour that can be accompanied by different paraneoplastic syndromes. Here we report a case of Type A thymoma associated with relapsing minimal change disease (MCD). This case highlights: (1) The need to balance rapid prednisolone weaning against risk for relapse in an elderly patient at risk for steroid-induced complications. (2) The addition of calcineurin inhibitor in relapsed thymoma-related MCD, to achieve steroid sparing effects. Resection of the offending tumour and prompt immunosuppressive therapy are critical in getting best renal and overall outcomes in this rare entity.
  5. Bijker R, Jiamsakul A, Uy E, Kumarasamy N, Ditango R, Chaiwarith R, et al.
    HIV Med, 2019 03;20(3):183-191.
    PMID: 30620108 DOI: 10.1111/hiv.12687
    OBJECTIVES: With aging of the HIV-positive population, cardiovascular disease (CVD) increasingly contributes to morbidity and mortality. We investigated CVD-related and other causes of death (CODs) and factors associated with CVD in a multi-country Asian HIV-positive cohort.

    METHODS: Patient data from 2003-2017 were obtained from the Therapeutics, Research, Education and AIDS Training in Asia (TREAT Asia) HIV Observational Database (TAHOD). We included patients on antiretroviral therapy (ART) with > 1 day of follow-up. Cumulative incidences were plotted for CVD-related, AIDS-related, non-AIDS-related, and unknown CODs, and any CVD (i.e. fatal and nonfatal). Competing risk regression was used to assess risk factors of any CVD.

    RESULTS: Of 8069 patients with a median follow-up of 7.3 years [interquartile range (IQR) 4.4-10.7 years], 378 patients died [incidence rate (IR) 6.2 per 1000 person-years (PY)], and this total included 22 CVD-related deaths (IR 0.36 per 1000 PY). Factors significantly associated with any CVD event (IR 2.2 per 1000 PY) were older age [sub-hazard ratio (sHR) 2.21; 95% confidence interval (CI) 1.36-3.58 for age 41-50 years; sHR 5.52; 95% CI 3.43-8.91 for ≥ 51 years, compared with < 40 years], high blood pressure (sHR 1.62; 95% CI 1.04-2.52), high total cholesterol (sHR 1.89; 95% CI 1.27-2.82), high triglycerides (sHR 1.55; 95% CI 1.02-2.37) and high body mass index (BMI) (sHR 1.66; 95% CI 1.12-2.46). CVD crude IRs were lower in the later ART initiation period and in lower middle- and upper middle-income countries.

    CONCLUSIONS: The development of fatal and nonfatal CVD events in our cohort was associated with older age, and treatable risk factors such as high blood pressure, triglycerides, total cholesterol and BMI. Lower CVD event rates in middle-income countries may indicate under-diagnosis of CVD in Asian-Pacific resource-limited settings.

  6. Jiamsakul A, Polizzotto M, Wen-Wei Ku S, Tanuma J, Hui E, Chaiwarith R, et al.
    J Acquir Immune Defic Syndr, 2019 03 01;80(3):301-307.
    PMID: 30531303 DOI: 10.1097/QAI.0000000000001918
    BACKGROUND: Hematological malignancies have continued to be highly prevalent among people living with HIV (PLHIV). This study assessed the occurrence of, risk factors for, and outcomes of hematological and nonhematological malignancies in PLHIV in Asia.

    METHODS: Incidence of malignancy after cohort enrollment was evaluated. Factors associated with development of hematological and nonhematological malignancy were analyzed using competing risk regression and survival time using Kaplan-Meier.

    RESULTS: Of 7455 patients, 107 patients (1%) developed a malignancy: 34 (0.5%) hematological [0.08 per 100 person-years (/100PY)] and 73 (1%) nonhematological (0.17/100PY). Of the hematological malignancies, non-Hodgkin lymphoma was predominant (n = 26, 76%): immunoblastic (n = 6, 18%), Burkitt (n = 5, 15%), diffuse large B-cell (n = 5, 15%), and unspecified (n = 10, 30%). Others include central nervous system lymphoma (n = 7, 21%) and myelodysplastic syndrome (n = 1, 3%). Nonhematological malignancies were mostly Kaposi sarcoma (n = 12, 16%) and cervical cancer (n = 10, 14%). Risk factors for hematological malignancy included age >50 vs. ≤30 years [subhazard ratio (SHR) = 6.48, 95% confidence interval (CI): 1.79 to 23.43] and being from a high-income vs. a lower-middle-income country (SHR = 3.97, 95% CI: 1.45 to 10.84). Risk was reduced with CD4 351-500 cells/µL (SHR = 0.20, 95% CI: 0.05 to 0.74) and CD4 >500 cells/µL (SHR = 0.14, 95% CI: 0.04 to 0.78), compared to CD4 ≤200 cells/µL. Similar risk factors were seen for nonhematological malignancy, with prior AIDS diagnosis showing a weak association. Patients diagnosed with a hematological malignancy had shorter survival time compared to patients diagnosed with a nonhematological malignancy.

    CONCLUSIONS: Nonhematological malignancies were common but non-Hodgkin lymphoma was more predominant in our cohort. PLHIV from high-income countries were more likely to be diagnosed, indicating a potential underdiagnosis of cancer in low-income settings.

  7. Jiamsakul A, Kiertiburanakul S, Ng OT, Chaiwarith R, Wong W, Ditangco R, et al.
    HIV Med, 2019 08;20(7):439-449.
    PMID: 30980495 DOI: 10.1111/hiv.12734
    OBJECTIVES: With earlier antiretroviral therapy (ART) initiation, time spent in HIV care is expected to increase. We aimed to investigate loss to follow-up (LTFU) in Asian patients who remained in care 5 years after ART initiation.

    METHODS: Long-term LTFU was defined as LTFU occurring after 5 years on ART. LTFU was defined as (1) patients not seen in the previous 12 months; and (2) patients not seen in the previous 6 months. Factors associated with LTFU were analysed using competing risk regression.

    RESULTS: Under the 12-month definition, the LTFU rate was 2.0 per 100 person-years (PY) [95% confidence interval (CI) 1.8-2.2 among 4889 patients included in the study. LTFU was associated with age > 50 years [sub-hazard ratio (SHR) 1.64; 95% CI 1.17-2.31] compared with 31-40 years, viral load ≥ 1000 copies/mL (SHR 1.86; 95% CI 1.16-2.97) compared with viral load < 1000 copies/mL, and hepatitis C coinfection (SHR 1.48; 95% CI 1.06-2.05). LTFU was less likely to occur in females, in individuals with higher CD4 counts, in those with self-reported adherence ≥ 95%, and in those living in high-income countries. The 6-month LTFU definition produced an incidence rate of 3.2 per 100 PY (95% CI 2.9-3.4 and had similar associations but with greater risks of LTFU for ART initiation in later years (2006-2009: SHR 2.38; 95% CI 1.93-2.94; and 2010-2011: SHR 4.26; 95% CI 3.17-5.73) compared with 2003-2005.

    CONCLUSIONS: The long-term LTFU rate in our cohort was low, with older age being associated with LTFU. The increased risk of LTFU with later years of ART initiation in the 6-month analysis, but not the 12-month analysis, implies that there was a possible move towards longer HIV clinic scheduling in Asia.

  8. Wong WJ, Mosiun JA, Hidayati Z, Balkis R, Sharif SZ, Lee D, et al.
    Breast, 2019 Aug;46:136-143.
    PMID: 31176055 DOI: 10.1016/j.breast.2019.05.016
    INTRODUCTION: Breast-conserving surgery (BCS) with radiation therapy is the procedure of choice for early-stage breast cancer. Survival and locoregional recurrence is non-inferior to mastectomy, with superior cosmetic and psycho-social outcomes. Differing health systems have demonstrated a wide variation in the rate of BCS. Little is known about the rate of BCS and factors influencing its practice in middle resource countries. This study aims to examine the BCS rates in Malaysia and to identify factors influencing its uptake.

    METHODOLOGY: This is a multi-centre, cross-sectional study involving the University of Malaya Medical Centre (UMMC), Queen Elizabeth II Hospital (QEH), and Tengku Ampuan Rahimah Hospital (TARH). Patients diagnosed with invasive breast cancer from January 2014 to December 2015 were included, excluding stromal cancers and lymphomas. Univariate and multivariate analyses identified factors influencing BCS.

    RESULTS: A total of 1005 patients were diagnosed with breast cancer in the allocated time frame. Excluding incomplete records and those who did not have surgery, 730 patients were analysed. Overall BCS rate was 32.9%. The BCS rate was highest at QEH (54.1%), followed by UMMC (29.5%), and TARH (17.4%). 16.9% had BCS after neoadjuvant therapy. Factors influencing BCS uptake included age, ethnic group, breast-surgeon led services, AJCC Stage, tumour size, HER-2 expression, and tumour grade.

    CONCLUSIONS: The rate of BCS in Malaysia is low. A wide variation of rate exists among the studied hospitals. Younger age, earlier AJCC stage, and the presence of a Breast sub-specialist surgeon, would make it more likely that the patient has her breast conserved.

  9. Low QJ, Cheo SW, Wong WH, Goh KS
    Med J Malaysia, 2019 Oct;74(5):445-446.
    PMID: 31649227
    Catamenial pneumothorax is a rare condition. We report a case of a 36-year-old female who presented with dyspnoea every time before she had her regular menses. Further investigation confirmed that she had catamenial pneumothorax. With this case we wish to highlight this rare diagnostic entity that every clinician should keep in mind.
  10. Loh C. Y., Tang, T. F., Wong, W. F., Looi, Chung Yeng
    MyJurnal
    Introduction: The Hedgehog (Hh) pathway serves as a major regulator in organ development, stem cell maintenance, cell proliferation, and cell differentiation. This pathway is highly regulated and aberrant activation will promote tumorigenesis. Hh pathway notably Sonic Hedgehog pathway was reported to be upregulated and promote tumorigenesis in various human malignancies including colorectal, gastric, lung, prostate, and breast. This review was aimed to discuss the current understanding of Hh pathway activation in different types of human cancers and discuss the development of the therapeutic applications targeting Hh pathway. Methods: A systematic review was conducted using the electronic research database PubMed Central (PMC) from 2014-2019. The search was limited to studies that are relevant to both Hh signalling pathway and human cancers. A total of 50 articles were selected and their references cited were searched and reviewed. Results: The results regarding the role of Hh signalling in pancreatic cancer and colorectal cancer are controversial with some reporting tumor promoting activities whereas others tumor suppressive activity. Besides, results from other studies suggesting that Hh signalling pathway plays an oncogenic role by inducing tumor cells proliferation, promoting metastasis and maintaining cancer stem cells in human cancers such as lung, stomach, and breast. To date, Glasdegib (PF-04449913) is the only Hh targeting small molecule inhibitor being studied at FDA Phase 3 clinical trial. Identification of the right tumors and minimization of the side effects remain as the main obstacles in the development of Hh signalling inhibitors. Conclusion: In conclusion, advancement in our understanding of Hh pathway has provided us opportunity to develop novel therapeutic strategies to fight human cancers with activated Hh pathway but more studies need to be conducted to solve the controversial regarding the role of Hh pathway in certain cancers.
  11. Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Dragicevic M, et al.
    Phys Rev Lett, 2020 Apr 03;124(13):131802.
    PMID: 32302170 DOI: 10.1103/PhysRevLett.124.131802
    A search is presented for a narrow resonance decaying to a pair of oppositely charged muons using sqrt[s]=13  TeV proton-proton collision data recorded at the LHC. In the 45-75 and 110-200 GeV resonance mass ranges, the search is based on conventional triggering and event reconstruction techniques. In the 11.5-45 GeV mass range, the search uses data collected with dimuon triggers with low transverse momentum thresholds, recorded at high rate by storing a reduced amount of trigger-level information. The data correspond to integrated luminosities of 137 and 96.6  fb^{-1} for conventional and high-rate triggering, respectively. No significant resonant peaks are observed in the probed mass ranges. The search sets the most stringent constraints to date on a dark photon in the ∼30-75 and 110-200 GeV mass ranges.
  12. Wong WK, Chua HS
    Knee Surg Relat Res, 2020 Apr 16;32(1):20.
    PMID: 32660589 DOI: 10.1186/s43019-020-00032-9
    BACKGROUND: In an ever-aging society that as a whole has become more affluent, significant emphasis has been accorded to an improved quality of life. Knee osteoarthritis is ever-increasingly treated with total knee arthroplasty. The benefits and satisfaction experienced by those who have undergone total knee replacements (TKR) are well documented in the literature. The issue arises when osteoarthritis of the affected knee is more complex than simple osteoarthritis, i.e. the patient has complex primary osteoarthritis. This collective term encompasses conditions such as massive bone loss, ligamentous laxity, coronal defects and those with contractures. There are various classifications to describe massive bone loss but we utilized the Anderson Orthopaedic Research Institute (AORI) classification. Numerous treatment options are available and we report the use of metaphyseal sleeves as a highly successful treatment option.

    METHODS: We retrospectively reviewed all the patients at our centre who underwent primary TKR using the metaphyseal sleeves. Patients were assessed on symptoms and functional status, and radiographs were also taken to assess for osseointegration. Only patients who completed 2 years of follow up were included in our study.

    RESULTS: The updated (2011) Knee Society Score (KSS) was used in conjunction with radiological assessments at each follow up. Mean KSS scores improved from 53.83 preoperatively to 193.39 postoperatively. All patients demonstrated increasing osseointegration throughout follow up.

    CONCLUSION: The metaphyseal sleeve is an excellent treatment option for complex primary osteoarthritic knees with good results objectively, functionally and radiologically and would be a great choice for all orthopaedic surgeons to include in their armamentarium.

  13. Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Dragicevic M, et al.
    Phys Rev Lett, 2020 Apr 24;124(16):162002.
    PMID: 32383915 DOI: 10.1103/PhysRevLett.124.162002
    The polarizations of promptly produced χ_{c1} and χ_{c2} mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at sqrt[s]=8  TeV. The χ_{c} states are reconstructed via their radiative decays χ_{c}→J/ψγ, with the photons being measured through conversions to e^{+}e^{-}, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_{c2} to χ_{c1} yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ→μ^{+}μ^{-} decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum.
  14. Najib MA, Noor-Izani NJ, Wan-Nor-Amilah WAW, Wong WK, Faez AM
    Trop Biomed, 2020 Jun 01;37(2):389-396.
    PMID: 33612808
    Human fascioliasis is a public health problem particularly in areas where ruminants are raised. The aims of this study were to determine the seroprevalence of anti-Fasciola antibody and the associated risk factors among cattle farm workers and dwellers in Kelantan. A total of 90 blood samples were collected in this cross-sectional study. A set of validated questionnaire was used to obtain information on socio-demographic profiles and dietary habits of participants. The sera were subjected to enzyme linked immunosorbent assay (ELISA) for the detection of anti-Fasciola IgG antibody. The association between seropositivity and the significant risk factors were determined via logistic regression. From the result, serological screening revealed 60 (67%) participants positive for anti-Fasciola IgG antibody. The factors found to be significantly associated with seropositivity against anti-Fasciola IgG antibody were the age group of 18 years old and above with calculated odds ratio of 3.2 times (p=0.032) and the duration of farming activities of more than 5 years with calculated odds ratio of 2.6 times (p=0.036). In conclusion, Fasciola infection is prevalent among cattle farm workers and dwellers in Kelantan.
  15. Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Dragicevic M, et al.
    Phys Rev Lett, 2020 Aug 07;125(6):061801.
    PMID: 32845700 DOI: 10.1103/PhysRevLett.125.061801
    The first observation of the tt[over ¯]H process in a single Higgs boson decay channel with the full reconstruction of the final state (H→γγ) is presented, with a significance of 6.6 standard deviations (σ). The CP structure of Higgs boson couplings to fermions is measured, resulting in an exclusion of the pure CP-odd structure of the top Yukawa coupling at 3.2σ. The measurements are based on a sample of proton-proton collisions at a center-of-mass energy sqrt[s]=13  TeV collected by the CMS detector at the LHC, corresponding to an integrated luminosity of 137  fb^{-1}. The cross section times branching fraction of the tt[over ¯]H process is measured to be σ_{tt[over ¯]H}B_{γγ}=1.56_{-0.32}^{+0.34}  fb, which is compatible with the standard model prediction of 1.13_{-0.11}^{+0.08}  fb. The fractional contribution of the CP-odd component is measured to be f_{CP}^{Htt}=0.00±0.33.
  16. Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Dragicevic M, et al.
    Phys Rev Lett, 2020 Oct 09;125(15):152001.
    PMID: 33095627 DOI: 10.1103/PhysRevLett.125.152001
    Using a data sample of proton-proton collisions at sqrt[s]=13  TeV, corresponding to an integrated luminosity of 140  fb^{-1} collected by the CMS experiment in 2016-2018, the B_{s}^{0}→X(3872)ϕ decay is observed. Decays into J/ψπ^{+}π^{-} and K^{+}K^{-} are used to reconstruct, respectively, the X(3872) and ϕ. The ratio of the product of branching fractions B[B_{s}^{0}→X(3872)ϕ]B[X(3872)→J/ψπ^{+}π^{-}] to the product B[B_{s}^{0}→ψ(2S)ϕ]B[ψ(2S)→J/ψπ^{+}π^{-}] is measured to be [2.21±0.29(stat)±0.17(syst)]%. The ratio B[B_{s}^{0}→X(3872)ϕ]/B[B^{0}→X(3872)K^{0}] is found to be consistent with one, while the ratio B[B_{s}^{0}→X(3872)ϕ]/B[B^{+}→X(3872)K^{+}] is two times smaller. This suggests a difference in the production dynamics of the X(3872) in B^{0} and B_{s}^{0} meson decays compared to B^{+}. The reported observation may shed new light on the nature of the X(3872) particle.
  17. Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Dragicevic M, et al.
    Phys Rev Lett, 2020 Oct 09;125(15):151802.
    PMID: 33095594 DOI: 10.1103/PhysRevLett.125.151802
    The first observation is reported of the combined production of three massive gauge bosons (VVV with V=W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV. The analysis is based on a data sample recorded by the CMS experiment at the CERN LHC corresponding to an integrated luminosity of 137  fb^{-1}. The searches for individual WWW, WWZ, WZZ, and ZZZ production are performed in final states with three, four, five, and six leptons (electrons or muons), or with two same-sign leptons plus one or two jets. The observed (expected) significance of the combined VVV production signal is 5.7 (5.9) standard deviations and the corresponding measured cross section relative to the standard model prediction is 1.02_{-0.23}^{+0.26}. The significances of the individual WWW and WWZ production are 3.3 and 3.4 standard deviations, respectively. Measured production cross sections for the individual triboson processes are also reported.
  18. Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Dragicevic M, et al.
    Phys Rev Lett, 2020 Nov 27;125(22):222001.
    PMID: 33315428 DOI: 10.1103/PhysRevLett.125.222001
    Ultrarelativistic heavy ion collisions recreate in the laboratory the thermodynamical conditions prevailing in the early universe up to 10^{-6}  sec, thereby allowing the study of the quark-gluon plasma (QGP), a state of quantum chromodynamics (QCD) matter with deconfined partons. The top quark, the heaviest elementary particle known, is accessible in nucleus-nucleus collisions at the CERN LHC, and constitutes a novel probe of the QGP. Here, we report the first evidence for the production of top quarks in nucleus-nucleus collisions, using lead-lead collision data at a nucleon-nucleon center-of-mass energy of 5.02 TeV recorded by the CMS experiment. Two methods are used to measure the cross section for top quark pair production (σ_{tt[over ¯]}) via the selection of charged leptons (electrons or muons) and bottom quarks. One method relies on the leptonic information alone, and the second one exploits, in addition, the presence of bottom quarks. The measured cross sections, σ_{tt[over ¯]}=2.54_{-0.74}^{+0.84} and 2.03_{-0.64}^{+0.71}  μb, respectively, are compatible with expectations from scaled proton-proton data and QCD predictions.
  19. Sirunyan AM, Tumasyan A, Adam W, Ambrogi F, Bergauer T, Dragicevic M, et al.
    Comput Softw Big Sci, 2020;4(1):10.
    PMID: 33196702 DOI: 10.1007/s41781-020-00041-z
    We describe a method to obtain point and dispersion estimates for the energies of jets arising from b quarks produced in proton-proton collisions at an energy of s = 13 TeV at the CERN LHC. The algorithm is trained on a large sample of simulated b jets and validated on data recorded by the CMS detector in 2017 corresponding to an integrated luminosity of 41 fb - 1 . A multivariate regression algorithm based on a deep feed-forward neural network employs jet composition and shape information, and the properties of reconstructed secondary vertices associated with the jet. The results of the algorithm are used to improve the sensitivity of analyses that make use of b jets in the final state, such as the observation of Higgs boson decay to b b ¯ .
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