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M Adams

Publications and source records attributed to M Adams.

At least 55 records · Page 3Linked to original sources
PubMed2004

Search for doubly charged higgs boson pair production in the decay to mu(+)mu(+)mu(-)mu(-) in pp collisions at sqrt[s]=1.96 TeV.

A search for pair production of doubly charged Higgs bosons in the process pp -->H(++)H(--) -->mu(+)mu(+)mu(-)mu(-) is performed with the D0 run II detector at the Fermilab Tevatron. The analysis is based on a sample of inclusive dimuon data collected at an energy of sqrt[s]=1.96 TeV, corresponding to an integrated luminosity of 113 pb(-1). In the absence of a signal, 95% confidence level mass limits of M(H(+/-+/-)(L))>118.4 GeV/c(2) and M(H(+/-+/-)(R))>98.2 GeV/c(2) are set for left-handed and right-handed doubly charged Higgs bosons, respectively, assuming 100% branching into muon pairs.

Journal Article↗
PubMed2004

A precision measurement of the mass of the top quark.

The standard model of particle physics contains parameters--such as particle masses--whose origins are still unknown and which cannot be predicted, but whose values are constrained through their interactions. In particular, the masses of the top quark (M(t)) and W boson (M(W)) constrain the mass of the long-hypothesized, but thus far not observed, Higgs boson. A precise measurement of M(t) can therefore indicate where to look for the Higgs, and indeed whether the hypothesis of a standard model Higgs is consistent with experimental data. As top quarks are produced in pairs and decay in only about 10(-24) s into various final states, reconstructing their masses from their decay products is very challenging. Here we report a technique that extracts more information from each top-quark event and yields a greatly improved precision (of +/- 5.3 GeV/c2) when compared to previous measurements. When our new result is combined with our published measurement in a complementary decay mode and with the only other measurements available, the new world average for M(t) becomes 178.0 +/- 4.3 GeV/c2. As a result, the most likely Higgs mass increases from the experimentally excluded value of 96 to 117 GeV/c2, which is beyond current experimental sensitivity. The upper limit on the Higgs mass at the 95% confidence level is raised from 219 to 251 GeV/c2.

Journal Article↗
PubMed2004

Search for narrow tt resonances in pp collisions at square root of (s)=1.8 TeV.

A search for narrow resonances that decay into tt pairs has been performed using 130 pb(-1) of data in the lepton + jets channel collected by the Dphi detector in pp collisions at square root of (s)=1.8 TeV. There is no significant deviation observed from the standard-model predictions at a top-quark mass of 175 GeV/c2. We therefore present upper limits at the 95% confidence level on the product of the production cross section and branching fraction to tt for narrow resonances as a function of the resonance mass MX. These limits are used to exclude the existence of a leptophobic top-color particle with mass MX<560 GeV/c2, using a theoretical cross section for a width GammaX=0.012MX.

Journal Article↗
PubMed2004

A phase IIA study of the topoisomerase I inhibitor, exatecan mesylate (DX-8951f), administered at two different dose schedules in patients with platinum- and taxane-resistant/refractory ovarian cancer.

OBJECTIVES: There is an urgent need for new agents with activity in platinum- and taxane-resistant epithelial ovarian cancer. Exatecan mesylate is a novel topoisomerase I inhibitor with potent activity against ovarian cancer in vitro. A multicentre phase IIA study was conducted in patients with platinum- and taxane-resistant epithelial ovarian cancer. PATIENTS AND METHODS: Fifty-seven patients with bidimensionally measurable ovarian cancer, previously exposed to platinum and taxanes, whose disease had relapsed within 6 months of platinum-containing chemotherapy were randomised to one of two intravenous schedules of exatecan mesylate; 0.3 mg/m(2) daily for 5 days every 3 weeks (Arm A) or 2.1 mg/m(2) weekly for 3 weeks out of 4 (Arm B). RESULTS: There were no responses in the weekly arm and a radiological response rate of 5.3% (95% CI 0.3-21.8%) in the daily arm. Principal toxicities were myelosuppression and emesis. Grade 3/4 neutropenia occurred in 29% of patients in Arm A and 6% patients in Arm B. Seventy-one percent of patients in Arm A required red cell transfusions while on treatment. CONCLUSIONS: Exatecan is well tolerated in this poor prognosis group of patients but only has modest single agent activity when administered in a daily regimen.

Adult↗
PubMed2004

International Campaign for Cures of Spinal Cord Injury Paralysis (ICCP): another step forward for spinal cord injury research.

For over 20 years, charitable organizations have worked to promote research that will cure the paralysis associated with spinal cord injury (SCI). When they began this quest, the consequences of SCI were thought to be permanent; that once damaged, the spinal cord could not be repaired. Today, the same organizations are credited with funding research that has realized many significant advances, brought new optimism and changed the outlook of researchers, clinicians and injured individuals alike. Progress in understanding the basic biology of spinal cord repair means that it is now a case of how soon useful treatments will be available, rather than if there will ever be anything to offer. With this in mind, many of the organizations that promote spinal cord research have formed an alliance to determine the ways in which their collaboration can hasten progress. The mission and objectives of this alliance, termed the International Campaign for Cures of Spinal Cord Injury Paralysis (ICCP), are described here.

Biomedical Research↗
PubMed2003

Search for large extra dimensions in the monojet+E(T) channel with the DØ detector.

We present a search for large extra dimensions (ED) in pp collisions at a center-of-mass energy of 1.8 TeV using data collected by the DØ detector at the Fermilab Tevatron in 1994-1996. Data corresponding to 78.8+/-3.9 pb(-1) are examined for events with large missing transverse energy, one high-p(T) jet, and no isolated muons. There is no excess observed beyond expectation from the standard model, and we place lower limits on the fundamental Planck scale of 1.0 and 0.6 TeV for 2 and 7 ED, respectively.

Journal Article↗
PubMed2003

Strongyloidiasis: an issue in Aboriginal communities.

Strongyloidiasis, a disease caused by the parasitic gut nematode (roundworm), Strongyloides stercoralis, has the highest prevalence in the world in rural and remote Aboriginal communities of northern Australia. With prevalences greater than 25%, these communities have rates of strongyloidiasis higher those in the worst affected developing countries where surveys have been recently conducted. Available data indisputably support that strongyloidiasis is more prevalent in rural and remote Aboriginal communities than in the mainstream Australian community. However control of strongyloidiasis has not been given a high priority by government health departments, with the result that Aboriginal people in remote and rural communities in Northern Australia are still suffering from a preventable and treatable disease. This article suggests that the only way to address the strongyloidiasis problem in Indigenous communities is to have strongyloidiasis recognised and addressed at the national level. One component of this must be making health departments responsible for establishing appropriate systems of effective treatment for and monitoring of patients with strongyloidiasis.

Journal Article↗
PubMed2003

Dendritic cell (DC) based therapy for cervical cancer: use of DC pulsed with tumour lysate and matured with a novel synthetic clinically non-toxic double stranded RNA analogue poly [I]:poly [C(12)U] (Ampligen R).

Human papilloma virus (HPV) found in 99.7% of cervical cancers represents an attractive immunotherapeutic target for novel adjuvant dendritic cell (DC) immunotherapy. DC primed with HPV antigens have been shown to be capable of inducing CTL responses powerful enough to eradicate established murine tumours expressing HPV16 antigen. The use of tumour lysate has been found to be an effective means of priming DC with tumour associated antigens in animal models and in clinical trials leading to significant anti-tumour responses. Autologous DC primed with sonicated HPV expressing tumour lysate have been shown to be capable of inducing HPV specific classes I and II T-cell immunity in a pilot clinical study.Synthetic double stranded polyribonucleotides are effective in vitro activation/maturation agents capable of inducing a stable mature DC phenotype producing high levels of IL12. However, the prototype polymer poly [I]:poly [G] has proved to be clinically toxic. Preliminary in vitro data have demonstrated that a novel clinically non-toxic analogue polymer poly [I]:poly [C(12)U] (Ampligen R) can effectively induce in vitro maturation of human monocyte derived DC with sustained bioactive IL12 production. Human monocyte derived DC primed with tumour lysate and matured with synthetic dsRNA may therefore offer an effective way of optimising Th1 specific anti-cancer T-cell responses in cancer patients. This strategy is currently being tested in a clinical trial in patients with cervical cancer.

Clinical Trials as Topic↗
PubMed2002

Search for the production of single sleptons through R-parity violation in pp; collisions at square root (s) =1.8 TeV.

We report the first search for supersymmetric particles via s-channel production and decay of smuons or muon sneutrinos at hadronic colliders. The data for the two-muon and two-jets final states were collected by the D0 experiment and correspond to an integrated luminosity of 94+/-5 pb(-1). Assuming that R parity is violated via the single coupling lambda'211, the number of candidate events is in agreement with expectation from the standard model. Exclusion contours are given in the (m(0),m(1/2)) and (m(x),m(v)) planes for lambda(')(211)=0.09, 0.08, and 0.07.

Journal Article↗
PubMed2002

Search for R-parity violating supersymmetry in two-muon and four-jet topologies.

We present results of a search for R-parity-violating decay of the neutralino chi;01, taken as the lightest supersymmetric particle, to a muon and two jets. The decay proceeds through a lepton-number violating coupling lambda(')(2jk) (j=1,2; k=1,2,3), with R-parity conservation in all other production and decay processes. In the absence of candidate events from 77.5+/-3.9 pb(-1) of data collected by the D0 experiment at the Fermilab Tevatron in pp collisions at sqrt[s]=1.8 TeV, and with an expected background of 0.18+/-0.03+/-0.02 events, we set limits on squark and gluino masses within the framework of the minimal low-energy supergravity-supersymmetry model.

Journal Article↗
PubMed2002

Search for leptoquark pairs decaying into nunu+jets in pp collisions at square root[s] = 1.8 TeV.

We present the results of a search for leptoquark (LQ) pairs in (85.2+/-3.7) pb(-1) of pp* collider data collected by the D0 experiment at the Fermilab Tevatron. We observe no evidence for leptoquark production and set a limit on sigma(pp*-->LQLQ-->nunu+jets) as a function of the mass of the leptoquark (m(LQ)). Assuming the decay LQ-->nuq, we exclude scalar leptoquarks for m(LQ) < 98 GeV/c(2), and vector leptoquarks for m(LQ) < 200 GeV/c(2) and coupling which produces the minimum cross section, at a 95% confidence level.

Journal Article↗
PubMed2002

Search for the scalar top quark in pp collisions at square root[s] = 1.8 TeV.

We have performed a search for scalar top quark (stop) pair production in the inclusive electron-muon-missing transverse energy final state, using a sample of pp events corresponding to 108.3 pb(-1) of data collected with the D0 detector at Fermilab. The search is done in the framework of the minimal supersymmetric standard model assuming that the sneutrino is the lightest supersymmetric particle. For the dominant decays of the lightest stop, t-->b chi+1 and t-->blnu, no evidence for signal is found. We derive cross-section limits as a function of stop ( t ), chargino ( chi+1), and sneutrino ( nu) masses.

Journal Article↗
PubMed2002

Direct search for charged higgs bosons in decays of top quarks.

We present a search for charged Higgs bosons in decays of pair-produced top quarks in pp collisions at sqrt[s] = 1.8 TeV recorded by the D0 detector at the Fermilab Tevatron collider. With no evidence for signal, we exclude most regions of the ( M(H+/-),tan(beta)) parameter space where the decay t--> H(+)b has a branching fraction >0.36 and B(H+/--->tau(nu)(tau)) is large.

Journal Article↗
PubMed2002

Sex chromosome elimination, X chromosome inactivation and reactivation in the southern brown bandicoot Isoodon obesulus (Marsupialia: Peramelidae).

Cytogenetic studies have shown that bandicoots (family Peramelidae) eliminate one X chromosome in females and the Y chromosome in males from some somatic tissues at different stages during development. The discovery of a polymorphism for X-linked phosphoglycerate kinase (PGK-1) in a population of Isoodon obesulus from Mount Gambier, South Australia, has allowed us to answer a number of long standing questions relating to the parental source of the eliminated X chromosome, X chromosome inactivation and reactivation in somatic and germ cells of female bandicoots. We have found no evidence of paternal PGK-1 allele expression in a wide range of somatic tissues and cell types from known female heterozygotes. We conclude that paternal X chromosome inactivation occurs in bandicoots as in other marsupial groups and that it is the paternally derived X chromosome that is eliminated from some cell types of females. The absence of PGK-1 paternal activity in somatic cells allowed us to examine the state of X chromosome activity in germ cells. Electrophoresis of germ cells from different aged pouch young heterozygotes showed only maternal allele expression in oogonia whereas an additional paternally derived band was observed in pre-dictyate oocytes. We conclude that reactivation of the inactive X chromosome occurs around the onset of meiosis in female bandicoots. As in other mammals, late replication is a common feature of the Y chromosome in male and the inactive X chromosome in female bandicoots. The basis of sex chromosome loss is still not known; however later timing of DNA synthesis is involved. Our finding that the paternally derived X chromosome is eliminated in females suggests that late DNA replication may provide the imprint for paternal X inactivation and the elimination of sex chromosomes in bandicoots.

Animals↗
PubMed2001

Ratio of isolated photon cross sections in pp macro collisions at square root of s = 630 and 1800 GeV.

The inclusive cross section for production of isolated photons has been measured in pp macro collisions at square root of s = 630 GeV with the D0 detector at the Fermilab Tevatron Collider. The photons span a transverse energy (E(T)) range from 7-49 GeV and have pseudorapidity absolute value of eta < 2.5. This measurement is combined with the previous D0 result at square root of s = 1800 GeV to form a ratio of the cross sections. Comparison of next-to-leading-order QCD with the measured cross section at 630 GeV and the ratio of cross sections show satisfactory agreement in most of the E(T) range.

Journal Article↗