Intracranial ependymomas of childhood: long-term outcome and prognostic factors

A detailed outcome analysis was performed on 40 children with intracranial ependymomas treated at our institution between 1975 and 1993 to identify those factors that were predictive of overall and progression-free survival. Three patients (7.5%) who were treated in the first 5 years of the study died within 3 months of surgery and were excluded from further outcome assessments. Eight (22%) of the 37 patients who survived the perioperative period had evidence of leptomeningeal dissemination at presentation, on the basis of either imaging (three children) and/or cytological (six children) results. The 5- and 10-year progression-free survival rates among these 37 patients were 45.1 and 36.1%, respectively; overall survival rates were 57.1 and 45.0%, respectively. The site of progression was local in 17 of 19 patients with progressive disease. Three factors were found to have a significant association (P < or = 0.05) with the outcome on both univariate and multivariate analyses: 1) the extent of the resection, 2) the age of the patient at diagnosis, and 3) the duration of the symptoms before diagnosis. The 5-year progression-free and overall survivals were 8.9 and 22%, respectively, among patients who had evidence of residual disease on postoperative imaging studies, compared with 68 and 80% rates among patients with no apparent residual disease (P = 0.0001 and P < 0.0001, respectively). Patients younger than 3 years fared significantly worse than older children (5-year progression-free and overall survival rates of 12 and 22%, respectively, in the younger children versus 60 and 75% in older children (P = 0.003 and P = 0.01, respectively). In addition, patients with a duration of symptoms before diagnosis of < 1 month had a worse outcome than those with a more protracted course (5-year progression-free and overall survival rates of 33 and 33%, respectively, versus rates of 53 and 64%, respectively (P = 0.02 for both). Neither the finding of evidence for dissemination at presentation nor the detection of anaplastic histological features (e.g., dense cellularity or high numbers of mitoses) were associated with a significantly worse outcome in this series. The combination of variables that had the strongest association with both favorable and unfavorable outcomes was the combination of the age of the patient and the resection extent. Only 2 of 17 patients older than 3 years with gross total resections have died, whereas 13 of 20 children who were either younger than 3 years or had radiologically incomplete resections have died (P < 0.0001).(ABSTRACT TRUNCATED AT 400 WORDS)

Waist-to-height ratio, body mass index and waist circumference for screening paediatric cardio-metabolic risk factors: a meta-analysis

Waist-to-height ratio (WHtR) is superior to body mass index and waist circumference for measuring adult cardio-metabolic risk factors. However, there is no meta-analysis to evaluate its discriminatory power in children and adolescents. A meta-analysis was conducted using multiple databases, including Embase and Medline. Studies were included that utilized receiver-operating characteristics curve analysis and published area under the receiver-operating characteristics curves (AUC) for adiposity indicators with hyperglycaemia, elevated blood pressure, dyslipidemia, metabolic syndrome and other cardio-metabolic outcomes. Thirty-four studies met the inclusion criteria. AUC values were extracted and pooled using a random-effects model and were weighted using the inverse variance method. The mean AUC values for each index were greater than 0.6 for most outcomes including hypertension. The values were the highest when screening for metabolic syndrome (AUC > 0.8). WHtR did not have significantly better screening power than other two indexes in most outcomes, except for elevated triglycerides when compared with body mass index and high metabolic risk score when compared with waist circumference. Although not being superior in discriminatory power, WHtR is convenient in terms of measurement and interpretation, which is advantageous in practice and allows for the quick identification of children with cardio-metabolic risk factors at an early age.

DNA sequence requirements for transcriptional initiator activity in mammalian cells

A transcriptional initiator (Inr) for mammalian RNA polymerase II can be defined as a DNA sequence element that overlaps a transcription start site and is sufficient for (i) determining the start site location in a promoter that lacks a TATA box and (ii) enhancing the strength of a promoter that contains a TATA box. We have prepared synthetic promoters containing random nucleotides downstream of Sp1 binding sites to determine the range of DNA sequences that convey Inr activity. Numerous sequences behaved as functional Inrs in an in vitro transcription assay, but the Inr activities varied dramatically. An examination of the functional elements revealed loose but consistent sequence requirements, with the approximate consensus sequence Py Py A+1 N T/A Py Py. Most importantly, almost every functional Inr that has been described fits into the consensus sequence that we have defined. Although several proteins have been reported to bind to specific Inrs, manipulation of those elements failed to correlate protein binding with Inr activity. The simplest model to explain these results is that all or most Inrs are recognized by a universal binding protein, similar to the functional recognition of all TATA sequences by the same TATA-binding protein. The previously reported proteins that bind near specific Inr elements may augment the strength of an Inr or may impart transcriptional regulation through an Inr.

Generality of a functional initiator consensus sequence

Transcriptional initiator (Inr) elements, like TATA boxes, are found in the core promoters of many eukaryotic protein-coding genes. To facilitate the dissection of transcription initiation mechanisms, and to identify Inr elements within known and newly-discovered genes, the precise DNA sequence requirements for Inr activity must be defined. Previously, we reported a preliminary Inr consensus sequence based on an extensive mutant analysis carried out in HeLa cell extracts. This analysis was limited, however, because it was performed only with an in vitro transcription assay and with the mutants in only one promoter context. In this study, we have assessed the general validity of the functional Inr consensus sequence by analyzing a selected set of mutants in additional promoter contexts and with both in vivo and in vitro assays. In addition, we analyzed the evolutionary conservation of the Inr consensus sequence by determining the sequence requirements for Inr function in Drosophila embryo extracts. The results demonstrate the generality and strict conservation among vertebrates and invertebrates of the Inr consensus sequence, Py Py A+1 N T/A Py Py.

LyF-1, a transcriptional regulator that interacts with a novel class of promoters for lymphocyte-specific genes

We have studied transcriptional control of the murine terminal deoxynucleotidyltransferase (TdT) gene, which is activated specifically in immature B and T lymphocytes. This analysis has led to the identification and purification of a 50-kDa sequence-specific DNA-binding protein, LyF-1, that interacts with the approximate consensus sequence PyPyTGGGAGPu and is enriched in cells at most stages of B- and T-cell differentiation. LyF-1 binds tightly to an element in the TdT promoter that we show is required for transcription in lymphocytes. LyF-1 also interacts with an element in the immunoglobulin mu enhancer, called microB, that was recently shown to be important for lymphocyte-specific enhancer activity. Moreover, LyF-1 binds to the promoters for the lymphocyte-specific genes lambda 5, VpreB, and lck, all of which we speculate have additional features in common with the TdT promoter. Thus, LyF-1 may be a general transcriptional activator for genes whose expression is restricted to the B- and/or T-lymphocyte lineages.

The lymphoid transcription factor LyF-1 is encoded by specific, alternatively spliced mRNAs derived from the Ikaros gene

The lymphocyte-specific DNA-binding protein LyF-1 interacts with a critical control element in the terminal deoxynucleotidyltransferase (TdT) promoter as well as with the promoters for other genes expressed during early stages of B- and T-cell development. We have purified LyF-1 and have obtained a partial amino acid sequence from proteolytic peptides. The amino acid sequence suggests that LyF-1 is a zinc finger protein encoded by the Ikaros gene, which previously was implicated in T-cell development. Recombinant Ikaros expressed in Escherichia coli bound to the TdT promoter, and antisera directed against the recombinant protein specifically blocked the DNA-binding activity of LyF-1 in crude extracts. Further analysis revealed that at least six distinct mRNAs are derived from the Ikaros/LyF-1 gene by alternative splicing. Only two of the isoforms possess the N-terminal zinc finger domain that is necessary and sufficient for TdT promoter binding. Although both of these isoforms bound to similar sequences in the TdT, lambda 5, VpreB, and lck promoters, one isoform contains an additional zinc finger that resulted in altered recognition of some binding sites. At least four of the Ikaros/LyF-1 isoforms were detectable in extracts from B- and T-cell lines, with the relative amounts of the isoforms varying considerably. These data reveal that the LyF-1 protein is encoded by specific mRNAs derived from the alternatively-spliced Ikaros gene, suggesting that this gene may be important for the early stages of both B- and T-lymphocyte development.

Creation of genome-wide protein expression libraries using random activation of gene expression

Here we report the use of random activation of gene expression (RAGE) to create genome-wide protein expression libraries. RAGE libraries containing only 5 x 10(6) individual clones were found to express every gene tested, including genes that are normally silent in the parent cell line. Furthermore, endogenous genes were activated at similar frequencies and expressed at similar levels within RAGE libraries created from multiple human cell lines, demonstrating that RAGE libraries are inherently normalized. Pools of RAGE clones were used to isolate 19,547 human gene clusters, approximately 53% of which were novel when tested against public databases of expressed sequence tag (EST) and complementary DNA (cDNA). Isolation of individual clones confirmed that the activated endogenous genes can be expressed at high levels to produce biologically active proteins. The properties of RAGE libraries and RAGE expression clones are well suited for a number of biotechnological applications including gene discovery, protein characterization, drug development, and protein manufacturing.

Intracranial ependymomas of childhood. Lack of correlation of histopathology and clinical outcome

The histopathology of 66 children with the diagnosis of ependymoma who were operated on at our institution between 1954 and 1994 were reviewed. We performed an initial analysis using the entire study cohort to determine which histopathological features associated with each other in a statistically significant fashion in an attempt to identify combinations of features that together might be useful in predicting outcome. A detailed outcome analysis was then performed on the 37 most recent cases who survived the postoperative period, in whom pre- and post-imaging studies as well as long term follow-up were obtained, in order to identify the histopathological features and combinations of features that were predictive of overall and progression-free survival. Five- and ten-year progression-free survivals were 45.1% and 36.1%, respectively. Overall survivals were 57.1% and 45.0%, respectively. Of the eight individual histopathological features, only the presence of necrosis was found to correlate with a less favorable overall and progression-free survival (PFS) (p = 0.06 and 0.03, respectively). In addition, the combination of necrosis with vascular proliferation or nuclear pleomorphism was associated with a worse PFS (p = 0.01 and 0.02, respectively). However, when other clinical predictive factors were included in a multivariate regression analysis, none of the histological features or combinations of features were independently associated with outcome. In addition, no relationship was found between the pattern of rosettes (true rosette, pseudorosette, or perivascular pseudorosette) and clinical outcome. In conclusion, although this study found an association between certain histopathological features and clinical outcome in children with ependymomas, these relationships did not reach statistical significance on multivariate analysis and, thus, do not provide sufficient evidence for modifying therapy based on histopathology alone.

Cloning and functional expression of a mouse liver organic cation transporter

Hepatic uptake of organic cations is essential for the metabolism and secretion of numerous endobiotics and drugs. Several hepatic organic cation transporters have been kinetically defined, yet have not been isolated or cloned. We have isolated a complementary DNA (cDNA) from both murine liver and kidney cDNA libraries (mOct1/Slc22a1), and have functionally expressed it in Xenopus laevis oocytes. Although mOct1/Slc22a1 is homologous to previously cloned rat and human organic cation transporters, organic cation transport kinetics differed markedly. mOct1/Slc22a1-RNA injection of oocytes resulted in the saturable, time- and temperature-dependent uptake of the quaternary organic cation [14C]-tetraethylammonium ([14C]-TEA), with a Km of 38 micromol/L. TEA uptake was inhibited by several other organic cation drugs, but was not inhibited by the organic cation n-methyl-nicotinamide (NMN), being instead stimulated by it (fourfold). [14C]-TEA uptake was also stimulated by an inside-outside proton gradient. mOct1/Slc22a1-injected oocytes transported the organic cations [3H]-1-methyl-4-phenylpyridium and [3H]-choline chloride, but did not transport other classes of organic compounds. mOct1/Slc22a1 encodes for a hepatic and renal organic cation transporter which may be important for the uptake and secretion of cationic drugs and endobiotics.

Observation of tt[over ¯]H Production

The observation of Higgs boson production in association with a top quark-antiquark pair is reported, based on a combined analysis of proton-proton collision data at center-of-mass energies of sqrt[s]=7, 8, and 13 TeV, corresponding to integrated luminosities of up to 5.1, 19.7, and 35.9  fb^{-1}, respectively. The data were collected with the CMS detector at the CERN LHC. The results of statistically independent searches for Higgs bosons produced in conjunction with a top quark-antiquark pair and decaying to pairs of W bosons, Z bosons, photons, τ leptons, or bottom quark jets are combined to maximize sensitivity. An excess of events is observed, with a significance of 5.2 standard deviations, over the expectation from the background-only hypothesis. The corresponding expected significance from the standard model for a Higgs boson mass of 125.09 GeV is 4.2 standard deviations. The combined best fit signal strength normalized to the standard model prediction is 1.26_{-0.26}^{+0.31}.

Exercise radionuclide ventriculography: practical considerations and sensitivity of coronary artery disease detection

Eighty-nine patients were evaluated for coronary artery disease (CAD) with exercise radionuclide ventriculography (ERV) and contrast coronary angiography. In 70 patients with documented lesions the ERV was abnormal in 65 for a sensitivity of 93%. In patients with normal coronary arteries, the ERV was abnormal in none for a specificity of 100%. Sensitivity of ERV for detecting CAD was affected by the level of exercise achieved. In patients with documented CAD who achieved adequate exercise (i.e., pressure rate product (PRP) greater than 250 or the development of angina or ST segment depression during exercise), the sensitivity was 98% (56 of 57 patients). In those with documented CAD who failed to achieve adequate exercise, the sensitivity was 69% (9 of 13 patients).

A comparison of treatment effectiveness between the CAD/CAM method and the manual method for managing adolescent idiopathic scoliosis

The treatment effectiveness of the CAD/CAM method and the manual method in managing adolescent idiopathic scoliosis (AIS) was compared. Forty subjects were recruited with twenty subjects for each method. The clinical parameters namely Cobb's angle and apical vertebral rotation were evaluated at the pre-brace and the immediate in-brace visits. The results demonstrated that orthotic treatments rendered by the CAD/CAM method and the conventional manual method were effective in providing initial control of Cobb's angle. Significant decreases (p < 0.05) were found between the pre-brace and immediate in-brace visits for both methods. The mean reductions of Cobb's angle were 12.8 degrees (41.9%) for the CAD/CAM method and 9.8 degrees (32.1%) for the manual method. An initial control of the apical vertebral rotation was not shown in this study. In the comparison between the CAD/CAM method and the manual method, no significant difference was found in the control of Cobb's angle and apical vertebral rotation. The current study demonstrated that the CAD/CAM method can provide similar result in the initial stage of treatment as compared with the manual method.

Results of irradiation in the squamous cell carcinomas of the anterior faucial pillar-retromolar trigone

Between January 1966 and August 1981, 159 patients with previously untreated squamous cell carcinomas of the anterior faucial pillar or retromolar trigone received definitive radiation therapy at The University of Texas M. D. Anderson Hospital and Tumor Institute. All except 11 patients were treated by external radiation including combination of electron beams with high-energy photons or 60Co to doses ranging from 60 Gy to 75 Gy. In the N0 patients, as a rule, only the ipsilateral subdigastric nodes were treated electively to a dose of 50 Gy. The 5-year determinate survival rate for the overall group was 83%. The cumulative recurrence rate showed that 92% of the patients had recurrence by 2 years. Therefore, all patients except those who died with no evidence of local disease less than 2 years after treatment were evaluated for local control. The failure rate for the evaluable patients was 29% for T1 lesions, 30% for T2 lesions, 24% for T3 lesions, and 40% for T4 lesions. After salvage surgery, which consisted of intraoral resection in one-third of the patients and of a composite operation in the other two-thirds, the ultimate failure rate was 0% for T1 lesions, 6% for T2 lesions, 8% for T3 lesions, and 20% for T4 lesions. Whereas stage was a poor indicator for treatment outcome, there was a significantly higher failure rate for infiltrative and/or ulcerated lesions (35%) than for exophytic or superficial lesions (15%). Histologic grade was of no prognostic significance, nor was there any significant difference in the failure rate for lesions originating on the anterior faucial pillar versus that for lesions on the retromolar trigone. Following radiotherapy, 30% of the patients developed some degree of bone exposure but only 5.6% (9 patients) required a segmental mandibular resection. The probability of bone exposure was not dose related and more likely reflected tumor location on the mucoperiosteum. Of the whole group, 16 patients (10%) experienced a neck failure with 8 ultimate failures after salvage surgery. Among the 16 patients who had neck failures, 13 were originally staged N0; 6 of these patients had failures that occurred in the electively treated ipsilateral subdigastric area, but the field was too small to cover the nodes adequately. Aspects of the radiotherapy techniques with combined electron and photon beams that may influence the treatment outcome are discussed.

Observation of Higgs Boson Decay to Bottom Quarks

The observation of the standard model (SM) Higgs boson decay to a pair of bottom quarks is presented. The main contribution to this result is from processes in which Higgs bosons are produced in association with a W or Z boson (VH), and are searched for in final states including 0, 1, or 2 charged leptons and two identified bottom quark jets. The results from the measurement of these processes in a data sample recorded by the CMS experiment in 2017, comprising 41.3  fb^{-1} of proton-proton collisions at sqrt[s]=13  TeV, are described. When combined with previous VH measurements using data collected at sqrt[s]=7, 8, and 13 TeV, an excess of events is observed at m_{H}=125  GeV with a significance of 4.8 standard deviations, where the expectation for the SM Higgs boson is 4.9. The corresponding measured signal strength is 1.01±0.22. The combination of this result with searches by the CMS experiment for H→bb[over ¯] in other production processes yields an observed (expected) significance of 5.6 (5.5) standard deviations and a signal strength of 1.04±0.20.

Inhibition of Cellular RNA polymerase II transcription by delta antigen of hepatitis delta virus

Hepatitis delta virus (HDV) contains a circular, viroid-like RNA and the hepatitis delta antigen (HDAg) protein. The viral RNA is replicated via RNA-dependent RNA synthesis, which is thought to be mediated by host DNA-dependent RNA polymerase II (pol II). The precise mechanism of HDV RNA replication using RNA as a template remains to be elucidated, though it is clear that HDAg is involved. We demonstrate here that both SP1-activated and basal pol II transcription are inhibited by HDAg. This inhibitory effect of HDAg was observed in vivo in transient cotransfection assays as well as in vitro in HeLa nuclear extracts with purified, recombinant HDAg. The in vitro inhibition of pol II transcription could be reversed with excess HeLa nuclear extracts. Furthermore, HDAg specifically inhibited pol II-mediated transcription but not pol I- or III-mediated transcription. These results provide support for the model in which HDAg participates in a complex with host cell pol II transcription factors to mediate pol II-dependent HDV RNA replication, concomitantly cellular pol II transcription.

The effects of perphenazine on the concentration of nortriptyline and its hydroxymetabolites in older patients

Twenty-five older patients who presented with psychotic depression were treated with a combination of nortriptyline and perphenazine. Plasma levels of nortriptyline, E-, and Z-10-OH nortriptyline (E- and Z-10-OH-NT) were measured before and after addition of perphenazine. The mean (+/-SD) initial nortriptyline dose was 59 +/- 24 mg/day, whereas the mean final nortriptyline and perphenazine doses were 56 +/- 24 and 19 +/- 13 mg/day, respectively. The mean plasma level to dose quotient for perphenazine (0.45 +/- 0.34 nM/mg/day) was comparable to the mean quotient reported previously in older psychotic patients treated with perphenazine alone. After addition of perphenazine, the median quotient of nortriptyline plasma level to nortriptyline dose (L/D) increased significantly (from 6.1 to 8.6). This change was inversely correlated with baseline nortriptyline L/D. The median ratio of E-10-OH-NT to nortriptyline plasma level decreased significantly (from 1.6 to 1.3), whereas the median ratio of Z-10-OH-NT to nortriptyline plasma level did not change significantly. These results are consistent with the known inhibition by perphenazine of the cytochrome P450 2D6 (sparteine/debrisoquine hydroxylase), the major enzyme involved in the oxidative metabolism of nortriptyline, mostly through the formation of E-10-OH-NT. This complex alteration in the metabolism of nortriptyline induced by perphenazine emphasizes the relevance of measuring plasma levels not only of nortriptyline but also of its hydroxymetabolites in older patients who are more likely to be sensitive to their differing cardiovascular, anticholinergic, and cognitive effects.

IbpA DR2 subunit immunization protects calves against Histophilus somni pneumonia

Histophilus somni is a prevalent cause of pneumonia and septicemia in cattle. Yet evidence for protection against pneumonia by current vaccines is controversial. We have identified a new H. somni virulence factor, IbpA. Previous studies implicated three likely protective subunits or domains in IbpA (A3, A5, and DR2), which were expressed as recombinant GST fusion proteins and purified for systemic vaccination of calves. After two subcutaneous immunizations, calves were challenged intrabronchially with virulent H. somni strain 2336 and clinical signs were monitored for four days before necropsy. Serum samples were collected throughout. At necropsy, the area of gross pneumonia was estimated, bronchial lavage fluid was collected, lesions were cultured and tissue samples were fixed for histopathology. Results showed that calves immunized with IbpA DR2 had a statistically lower percentage of lung with gross lesions than controls, fewer histologic abnormalities in affected areas and no H. somni isolated from residual pneumonic lesions. Calves immunized with the control GST vaccine, IbpA3 or IbpA5 had larger H. somni positive pneumonic lesions. ELISA results for serum antibodies showed that calves immunized with the IbpA DR2 antigen had high IgG1 and IgG2 and lowest IgE responses to the immunizing antigen. Specific IgG responses were also high in the bronchial lavage fluid. High specific serum IgE responses were previously shown to be associated with more severe pneumonia, but high IgG specific anti-IbpA DR2 responses seem to be critically related to protection. Since the IbpA DR2 Fic motif has been shown to cause bovine alveolar cells to retract, we tested the neutralizing ability of pooled serum from the IbpA DR2 immunized group. This pooled serum reduced cytotoxicity by 75-80%, suggesting that the protection was due to antibody neutralization of IbpA cytotoxicity, at least in part. Therefore, IbpA DR2 appears to be an important protective antigen of H. somni. The study shows, for the first time, that immunization with a purified Fic protein protects against disease in a natural host.

Exercise radionuclide ejection fraction: correlation with exercise contrast ventriculography

Thirty-one patients with known or suspected coronary artery disease or aortic valvular disease were studied at rest and during supine bicycle exercise with radionuclide and contrast left ventriculography. The radionuclide ejection fractions calculated independently by three observers correlated well at rest (r = 0.96) and with exercise (r = 0.94). The calculated values also correlated well with those obtained for contrast ventriculography using the area-length method Dodge (r = 0.89 at rest and r = 0.90 with exercise). The results suggest that further clinical applications of exercise radionuclide ventriculography are justified.

Characterization of mRNA for hepatitis delta antigen: exclusion of the full-length antigenomic RNA as an mRNA

Hepatitis delta virus (HDV) encodes a single protein, the hepatitis delta antigen (HDAg), which is thought to be translated from a 0. 8-kb RNA of antigenomic sense. This subgenomic RNA species is present in very small amounts in HDV-infected liver tissues and in cultured cells infected or transfected with HDV, and in some cases it cannot be detected at all. In contrast, HDAg protein is present in large amounts in all natural and experimental models of HDV infection. This study addresses whether other HDV RNA species, such as the antigenomic-sense, genome-size HDV RNA can also serve as the mRNA for HDAg synthesis. Taking advantage of the ability of herpes simplex virus (HSV) to degrade only polyadenylated mRNAs, we examined the effect of HSV coinfection on HDAg synthesis. It was shown that HSV infection did degrade the subgenomic 0.8-kb HDV mRNA but not HDV genome-length RNA. Under such conditions, HDAg synthesis was completely inhibited. Furthermore, the genome-length HDV RNA was found not to be associated with polysomes. Finally, in vitro translation studies demonstrated that HDAg could not be translated directly from the genome-length antigenomic-sense HDV RNA. These results suggest that only the subgenomic RNA species of HDV possesses properties characteristic of the mRNA for HDAg and that the genome-length RNA cannot be used for translating HDAg. In addition, we found that HDV RNA replication did not depend on de novo HDAg synthesis.

Search for a Narrow Resonance Lighter than 200 GeV Decaying to a Pair of Muons in Proton-Proton Collisions at sqrt[s]=13 TeV

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.

Measurement of Prompt D^{0} Meson Azimuthal Anisotropy in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

The prompt D^{0} meson azimuthal anisotropy coefficients, v_{2} and v_{3}, are measured at midrapidity (|y|<1.0) in Pb-Pb collisions at a center-of-mass energy sqrt[s_{NN}]=5.02  TeV per nucleon pair with data collected by the CMS experiment. The measurement is performed in the transverse momentum (p_{T}) range of 1 to 40  GeV/c, for central and midcentral collisions. The v_{2} coefficient is found to be positive throughout the p_{T} range studied. The first measurement of the prompt D^{0} meson v_{3} coefficient is performed, and values up to 0.07 are observed for p_{T} around 4  GeV/c. Compared to measurements of charged particles, a similar p_{T} dependence, but smaller magnitude for p_{T}<6  GeV/c, is found for prompt D^{0} meson v_{2} and v_{3} coefficients. The results are consistent with the presence of collective motion of charm quarks at low p_{T} and a path length dependence of charm quark energy loss at high p_{T}, thereby providing new constraints on the theoretical description of the interactions between charm quarks and the quark-gluon plasma.

Search for Heavy Neutral Leptons in Events with Three Charged Leptons in Proton-Proton Collisions at sqrt[s]=13 TeV

A search for a heavy neutral lepton N of Majorana nature decaying into a W boson and a charged lepton is performed using the CMS detector at the LHC. The targeted signature consists of three prompt charged leptons in any flavor combination of electrons and muons. The data were collected in proton-proton collisions at a center-of-mass energy of 13 TeV, with an integrated luminosity of 35.9  fb^{-1}. The search is performed in the N mass range between 1 GeV and 1.2 TeV. The data are found to be consistent with the expected standard model background. Upper limits are set on the values of |V_{eN}|^{2} and |V_{μN}|^{2}, where V_{ℓN} is the matrix element describing the mixing of N with the standard model neutrino of flavor ℓ. These are the first direct limits for N masses above 500 GeV and the first limits obtained at a hadron collider for N masses below 40 GeV.