Search for exotic decays of the Higgs boson to a pair of pseudoscalars in the μμbb and ττbb final states

A search for exotic decays of the Higgs boson (H ) with a mass of 125Ge V to a pair of light pseudoscalars a 1 is performed in final states where one pseudoscalar decays to two b quarks and the other to a pair of muons or τ leptons. A data sample of proton-proton collisions at s = 13 Te V corresponding to an integrated luminosity of 138fb - 1 recorded with the CMS detector is analyzed. No statistically significant excess is observed over the standard model backgrounds. Upper limits are set at 95% confidence level (CL ) on the Higgs boson branching fraction to μ μ b b and to τ τ b b , via a pair of a 1 s. The limits depend on the pseudoscalar mass m a 1 and are observed to be in the range (0.17-3.3) × 10 - 4 and (1.7-7.7) × 10 - 2 in the μ μ b b and τ τ b b final states, respectively. In the framework of models with two Higgs doublets and a complex scalar singlet (2HDM+S), the results of the two final states are combined to determine upper limits on the branching fraction B ( H → a 1 a 1 → ℓ ℓ b b ) at 95% CL , with ℓ being a muon or a τ lepton. For different types of 2HDM+S, upper bounds on the branching fraction B ( H → a 1 a 1 ) are extracted from the combination of the two channels. In most of the Type II 2HDM+S parameter space, B ( H → a 1 a 1 ) values above 0.23 are excluded at 95% CL for m a 1 values between 15 and 60Ge V .

Observation of WWγ Production and Search for Hγ Production in Proton-Proton Collisions at sqrt[s]=13 TeV

The observation of WWγ production in proton-proton collisions at a center-of-mass energy of 13 TeV with an integrated luminosity of 138  fb^{-1} is presented. The observed (expected) significance is 5.6 (5.1) standard deviations. Events are selected by requiring exactly two leptons (one electron and one muon) of opposite charge, moderate missing transverse momentum, and a photon. The measured fiducial cross section for WWγ is 5.9±0.8(stat)±0.8(syst)±0.7(modeling)  fb, in agreement with the next-to-leading order quantum chromodynamics prediction. The analysis is extended with a search for the associated production of the Higgs boson and a photon, which is generated by a coupling of the Higgs boson to light quarks. The result is used to constrain the Higgs boson couplings to light quarks.

New Structures in the J/ψJ/ψ Mass Spectrum in Proton-Proton Collisions at sqrt[s]=13 TeV

A search is reported for near-threshold structures in the J/ψJ/ψ invariant mass spectrum produced in proton-proton collisions at sqrt[s]=13  TeV from data collected by the CMS experiment, corresponding to an integrated luminosity of 135  fb^{-1}. Three structures are found, and a model with quantum interference among these structures provides a good description of the data. A new structure is observed with a local significance above 5 standard deviations at a mass of 6638_{-38}^{+43}(stat)_{-31}^{+16}(syst)  MeV. Another structure with even higher significance is found at a mass of 6847_{-28}^{+44}(stat)_{-20}^{+48}(syst)  MeV, which is consistent with the X(6900) resonance reported by the LHCb experiment and confirmed by the ATLAS experiment. Evidence for another new structure, with a local significance of 4.7 standard deviations, is found at a mass of 7134_{-25}^{+48}(stat)_{-15}^{+41}(syst)  MeV. Results are also reported for a model without interference, which does not fit the data as well and shows mass shifts up to 150 MeV relative to the model with interference.

Search for Scalar Leptoquarks Produced via τ-Lepton-Quark Scattering in pp Collisions at sqrt[s]=13 TeV

The first search for scalar leptoquarks produced in τ-lepton-quark collisions is presented. It is based on a set of proton-proton collision data recorded with the CMS detector at the LHC at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 138  fb^{-1}. The reconstructed final state consists of a jet, significant missing transverse momentum, and a τ lepton reconstructed through its hadronic or leptonic decays. Limits are set on the product of the leptoquark production cross section and branching fraction and interpreted as exclusions in the plane of the leptoquark mass and the leptoquark-τ-quark coupling strength.

Search for Inelastic Dark Matter in Events with Two Displaced Muons and Missing Transverse Momentum in Proton-Proton Collisions at sqrt[s]=13 TeV

A search for dark matter in events with a displaced nonresonant muon pair and missing transverse momentum is presented. The analysis is performed using an integrated luminosity of 138  fb^{-1} of proton-proton (pp) collision data at a center-of-mass energy of 13 TeV produced by the LHC in 2016-2018. No significant excess over the predicted backgrounds is observed. Upper limits are set on the product of the inelastic dark matter production cross section σ(pp→A^{'}→χ_{1}χ_{2}) and the decay branching fraction B(χ_{2}→χ_{1}μ^{+}μ^{-}), where A^{'} is a dark photon and χ_{1} and χ_{2} are states in the dark sector with near mass degeneracy. This is the first dedicated collider search for inelastic dark matter.

Luminosity determination using Z boson production at the CMS experiment

The measurement of Z boson production is presented as a method to determine the integrated luminosity of CMS data sets. The analysis uses proton-proton collision data, recorded by the CMS experiment at the CERN LHC in 2017 at a center-of-mass energy of 13Te V . Events with Z bosons decaying into a pair of muons are selected. The total number of Z bosons produced in a fiducial volume is determined, together with the identification efficiencies and correlations from the same data set, in small intervals of 20pb - 1 of integrated luminosity, thus facilitating the efficiency and rate measurement as a function of time and instantaneous luminosity. Using the ratio of the efficiency-corrected numbers of Z bosons, the precisely measured integrated luminosity of one data set is used to determine the luminosity of another. For the first time, a full quantitative uncertainty analysis of the use of Z  bosons for the integrated luminosity measurement is performed. The uncertainty in the extrapolation between two data sets, recorded in 2017 at low and high instantaneous luminosity, is less than 0.5%. We show that the Z boson rate measurement constitutes a precise method, complementary to traditional methods, with the potential to improve the measurement of the integrated luminosity.

Measurement of the production cross section for a W boson in association with a charm quark in proton-proton collisions at s=13TeV

The strange quark content of the proton is probed through the measurement of the production cross section for a W boson and a charm (c) quark in proton-proton collisions at a center-of-mass energy of 13Te V . The analysis uses a data sample corresponding to a total integrated luminosity of 138fb - 1 collected with the CMS detector at the LHC. The W bosons are identified through their leptonic decays to an electron or a muon, and a neutrino. Charm jets are tagged using the presence of a muon or a secondary vertex inside the jet. The W + c production cross section and the cross section ratio R c ± = σ ( W + + c ¯ ) / σ ( W - + c ) are measured inclusively and differentially as functions of the transverse momentum and the pseudorapidity of the lepton originating from the W boson decay. The precision of the measurements is improved with respect to previous studies, reaching 1% in R c ± = 0.950 ± 0.005 (stat) ± 0.010 (syst) . The measurements are compared with theoretical predictions up to next-to-next-to-leading order in perturbative quantum chromodynamics.

A naïve comparison to assess the success of ultra-short implants

Introduction

Conventional implants are associated with ridge augmentation/sinus lift procedures in vertically insufficient ridges, which increase morbidity and healing time. Short implants provided some hope in this context. The present study considered the use of ultra-short implants in vertically insufficient posterior mandibular ridges and evaluated their success. Hence, study was done to evaluate the success of ultra-short implants in partially edentulous posterior mandible clinically and radiographically.

Materials and Methods

The study is a "Naïve direct comparison" of ultra-short implants to conventional implants for assessing their success in vertically insufficient posterior mandibular ridges. A total of 10 ultra-short implants were placed in a partially edentulous posterior mandibular ridge with at least 8-mm horizontal (at crest) and vertical dimensions. A delayed loading was done at three-month follow-up. Data acquisition was done at baseline (immediately after loading), 6-, 9-, 12-month intervals. Parameters assessed were marginal bone loss (MBL), probing pocket depth reduction (PPDR), modified plaque index (mPI), modified gingival index (mGI).

Results

All the placed 10 implants survived, and no failure was observed. "Independent sample t-test" and "paired sample t-test" was done for intergroup and intragroup analysis, respectively. Intergroup comparison between the ultra-short and conventional implants presented a statistically insignificant difference between all the parameters at all the follow-up visits (baseline, 6-, 9-, 12 months).

Conclusions

Within the limitations, it was thus concluded that ultra-short implants may be considered as a viable treatment option for vertically insufficient mandibular ridge. Further, long-term randomized controlled trials are required to establish the evidence.

Probing Small Bjorken-x Nuclear Gluonic Structure via Coherent J/ψ Photoproduction in Ultraperipheral Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

Quasireal photons exchanged in relativistic heavy ion interactions are powerful probes of the gluonic structure of nuclei. The coherent J/ψ photoproduction cross section in ultraperipheral lead-lead collisions is measured as a function of photon-nucleus center-of-mass energies per nucleon (W_{γN}^{Pb}) over a wide range of 40 Collapse

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Measurement of the top quark mass using a profile likelihood approach with the lepton + jets final states in proton-proton collisions at s=13TeV

The mass of the top quark is measured in 36.3fb - 1 of LHC proton-proton collision data collected with the CMS detector at s = 13 Te V . The measurement uses a sample of top quark pair candidate events containing one isolated electron or muon and at least four jets in the final state. For each event, the mass is reconstructed from a kinematic fit of the decay products to a top quark pair hypothesis. A profile likelihood method is applied using up to four observables per event to extract the top quark mass. The top quark mass is measured to be 171.77 ± 0.37 Ge V . This approach significantly improves the precision over previous measurements.

A search for decays of the Higgs boson to invisible particles in events with a top-antitop quark pair or a vector boson in proton-proton collisions at s=13TeV

A search for decays to invisible particles of Higgs bosons produced in association with a top-antitop quark pair or a vector boson, which both decay to a fully hadronic final state, has been performed using proton-proton collision data collected at s = 13 Te V by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138fb - 1 . The 95% confidence level upper limit set on the branching fraction of the 125Ge V Higgs boson to invisible particles, B ( H → inv ) , is 0.54 (0.39 expected), assuming standard model production cross sections. The results of this analysis are combined with previous B ( H → inv ) searches carried out at s = 7 , 8, and 13Te V in complementary production modes. The combined upper limit at 95% confidence level on B ( H → inv ) is 0.15 (0.08 expected).

Observation of τ Lepton Pair Production in Ultraperipheral Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

We present an observation of photon-photon production of τ lepton pairs in ultraperipheral lead-lead collisions. The measurement is based on a data sample with an integrated luminosity of 404  μb^{-1} collected by the CMS experiment at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=5.02  TeV. The γγ→τ^{+}τ^{-} process is observed for τ^{+}τ^{-} events with a muon and three charged hadrons in the final state. The measured fiducial cross section is σ(γγ→τ^{+}τ^{-})=4.8±0.6(stat)±0.5(syst)  μb, where the second (third) term corresponds to the statistical (systematic) uncertainty in σ(γγ→τ^{+}τ^{-}) in agreement with leading-order QED predictions. Using σ(γγ→τ^{+}τ^{-}), we estimate a model-dependent value of the anomalous magnetic moment of the τ lepton of a_{τ}=0.001_{-0.089}^{+0.055}.

Measurement of the Dependence of the Hadron Production Fraction Ratios f_{s}/f_{u} and f_{d}/f_{u} on B Meson Kinematic Variables in Proton-Proton Collisions at sqrt[s]=13 TeV

The dependence of the ratio between the B_{s}^{0} and B^{+} hadron production fractions, f_{s}/f_{u}, on the transverse momentum (p_{T}) and rapidity of the B mesons is studied using the decay channels B_{s}^{0}→J/ψϕ and B^{+}→J/ψK^{+}. The analysis uses a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment in 2018 and corresponding to an integrated luminosity of 61.6  fb^{-1}. The f_{s}/f_{u} ratio is observed to depend on the B p_{T} and to be consistent with becoming asymptotically constant at large p_{T}. No rapidity dependence is observed. The ratio of the B^{0} to B^{+} meson production fractions, f_{d}/f_{u}, is also measured, for the first time in proton-proton collisions, using the B^{0}→J/ψK^{*0} decay channel. The result is found to be within 1 standard deviation of unity and independent of p_{T} and rapidity, as expected from isospin invariance.

Search for Exotic Higgs Boson Decays H→AA→4γ with Events Containing Two Merged Diphotons in Proton-Proton Collisions at sqrt[s]=13 TeV

We present the first direct search for exotic Higgs boson decays H→AA, A→γγ in events with two photonlike objects. The hypothetical particle A is a low-mass spin-0 particle decaying promptly to a merged diphoton reconstructed as a single photonlike object. We analyze the data collected by the CMS experiment at sqrt[s]=13  TeV corresponding to an integrated luminosity of 136  fb^{-1}. No excess above the estimated background is found. We set upper limits on the branching fraction B(H→AA→4γ) of (0.9-3.3)×10^{-3} at 95% confidence level for masses of A in the range 0.1-1.2 GeV.

Observation of Same-Sign WW Production from Double Parton Scattering in Proton-Proton Collisions at sqrt[s]=13 TeV

The first observation of the production of W^{±}W^{±} bosons from double parton scattering processes using same-sign electron-muon and dimuon events in proton-proton collisions is reported. The data sample corresponds to an integrated luminosity of 138  fb^{-1} recorded at a center-of-mass energy of 13 TeV using the CMS detector at the CERN LHC. Multivariate discriminants are used to distinguish the signal process from the main backgrounds. A binned maximum likelihood fit is performed to extract the signal cross section. The measured cross section for production of same-sign W bosons decaying leptonically is 80.7±11.2(stat) _{-8.6}^{+9.5}(syst)±12.1(model)  fb, whereas the measured fiducial cross section is 6.28±0.81(stat)±0.69(syst)±0.37(model)  fb. The observed significance of the signal is 6.2 standard deviations above the background-only hypothesis.

Observation of the Rare Decay of the η Meson to Four Muons

A search for the rare η→μ^{+}μ^{-}μ^{+}μ^{-} double-Dalitz decay is performed using a sample of proton-proton collisions, collected by the CMS experiment at the CERN LHC with high-rate muon triggers during 2017 and 2018 and corresponding to an integrated luminosity of 101  fb^{-1}. A signal having a statistical significance well in excess of 5 standard deviations is observed. Using the η→μ^{+}μ^{-} decay as normalization, the branching fraction B(η→μ^{+}μ^{-}μ^{+}μ^{-})=[5.0±0.8(stat)±0.7(syst)±0.7(B_{2μ})]×10^{-9} is measured, where the last term is the uncertainty in the normalization channel branching fraction. This work achieves an improved precision of over 5 orders of magnitude compared to previous results, leading to the first measurement of this branching fraction, which is found to agree with theoretical predictions.

Search for Higgs Boson Decay to a Charm Quark-Antiquark Pair in Proton-Proton Collisions at sqrt[s]=13 TeV

A search for the standard model Higgs boson decaying to a charm quark-antiquark pair, H→cc[over ¯], produced in association with a leptonically decaying V (W or Z) boson is presented. The search is performed with proton-proton collisions at sqrt[s]=13  TeV collected by the CMS experiment, corresponding to an integrated luminosity of 138  fb^{-1}. Novel charm jet identification and analysis methods using machine learning techniques are employed. The analysis is validated by searching for Z→cc[over ¯] in VZ events, leading to its first observation at a hadron collider with a significance of 5.7 standard deviations. The observed (expected) upper limit on σ(VH)B(H→cc[over ¯]) is 0.94 (0.50_{-0.15}^{+0.22})pb at 95% confidence level (C.L.), corresponding to 14 (7.6_{-2.3}^{+3.4}) times the standard model prediction. For the Higgs-charm Yukawa coupling modifier, κ_{c}, the observed (expected) 95% C.L. interval is 1.1<|κ_{c}|<5.5 (|κ_{c}|<3.4), the most stringent constraint to date.

Search for Nonresonant Pair Production of Highly Energetic Higgs Bosons Decaying to Bottom Quarks

A search for nonresonant Higgs boson (H) pair production via gluon and vector boson (V) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138  fb^{-1} collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted H pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the H self-coupling and the quartic VVHH couplings, κ_{2V}, excluding κ_{2V}=0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.

Search for Higgs Boson and Observation of Z Boson through Their Decay into a Charm Quark-Antiquark Pair in Boosted Topologies in Proton-Proton Collisions at sqrt[s]=13 TeV

A search for the standard model (SM) Higgs boson (H) produced with transverse momentum (p_{T}) greater than 450 GeV and decaying to a charm quark-antiquark (cc[over ¯]) pair is presented. The search is performed using proton-proton collision data collected at sqrt[s]=13  TeV by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138  fb^{-1}. Boosted H→cc[over ¯] decay products are reconstructed as a single large-radius jet and identified using a deep neural network charm tagging technique. The method is validated by measuring the Z→cc[over ¯] decay process, which is observed in association with jets at high p_{T} for the first time with a signal strength of 1.00_{-0.14}^{+0.17}(syst)±0.08(theo)±0.06(stat), defined as the ratio of the observed process rate to the SM expectation. The observed (expected) upper limit on σ(H)B(H→cc[over ¯]) is set at 47 (39) times the SM prediction at 95% confidence level.

Measurements of the Higgs boson production cross section and couplings in the W boson pair decay channel in proton-proton collisions at s=13TeV

Production cross sections of the standard model Higgs boson decaying to a pair of W bosons are measured in proton-proton collisions at a center-of-mass energy of 13Te V . The analysis targets Higgs bosons produced via gluon fusion, vector boson fusion, and in association with a W or Z boson. Candidate events are required to have at least two charged leptons and moderate missing transverse momentum, targeting events with at least one leptonically decaying W boson originating from the Higgs boson. Results are presented in the form of inclusive and differential cross sections in the simplified template cross section framework, as well as couplings of the Higgs boson to vector bosons and fermions. The data set collected by the CMS detector during 2016-2018 is used, corresponding to an integrated luminosity of 138fb - 1 . The signal strength modifier μ , defined as the ratio of the observed production rate in a given decay channel to the standard model expectation, is measured to be μ = 0 . 95 - 0.09 + 0.10 . All results are found to be compatible with the standard model within the uncertainties.

Probing Heavy Majorana Neutrinos and the Weinberg Operator through Vector Boson Fusion Processes in Proton-Proton Collisions at sqrt[s]=13 TeV

The first search exploiting the vector boson fusion process to probe heavy Majorana neutrinos and the Weinberg operator at the LHC is presented. The search is performed in the same-sign dimuon final state using a proton-proton collision dataset recorded at sqrt[s]=13  TeV, collected with the CMS detector and corresponding to a total integrated luminosity of 138  fb^{-1}. The results are found to agree with the predictions of the standard model. For heavy Majorana neutrinos, constraints on the squared mixing element between the muon and the heavy neutrino are derived in the heavy neutrino mass range 50 GeV-25 TeV; for masses above 650 GeV these are the most stringent constraints from searches at the LHC to date. A first test of the Weinberg operator at colliders provides an observed upper limit at 95% confidence level on the effective μμ Majorana neutrino mass of 10.8 GeV.

Measurement of the differential tt¯ production cross section as a function of the jet mass and extraction of the top quark mass in hadronic decays of boosted top quarks

A measurement of the jet mass distribution in hadronic decays of Lorentz-boosted top quarks is presented. The measurement is performed in the lepton + jets channel of top quark pair production (t t ¯ ) events, where the lepton is an electron or muon. The products of the hadronic top quark decay are reconstructed using a single large-radius jet with transverse momentum greater than 400Ge V . The data were collected with the CMS detector at the LHC in proton-proton collisions and correspond to an integrated luminosity of 138fb - 1 . The differential t t ¯ production cross section as a function of the jet mass is unfolded to the particle level and is used to extract the top quark mass. The jet mass scale is calibrated using the hadronic W boson decay within the large-radius jet. The uncertainties in the modelling of the final state radiation are reduced by studying angular correlations in the jet substructure. These developments lead to a significant increase in precision, and a top quark mass of 173.06 ± 0.84 Ge V .

A portrait of the Higgs boson by the CMS experiment ten years after the discovery

In July 2012, the ATLAS and CMS collaborations at the CERN Large Hadron Collider announced the observation of a Higgs boson at a mass of around 125 gigaelectronvolts. Ten years later, and with the data corresponding to the production of a 30-times larger number of Higgs bosons, we have learnt much more about the properties of the Higgs boson. The CMS experiment has observed the Higgs boson in numerous fermionic and bosonic decay channels, established its spin-parity quantum numbers, determined its mass and measured its production cross-sections in various modes. Here the CMS Collaboration reports the most up-to-date combination of results on the properties of the Higgs boson, including the most stringent limit on the cross-section for the production of a pair of Higgs bosons, on the basis of data from proton-proton collisions at a centre-of-mass energy of 13 teraelectronvolts. Within the uncertainties, all these observations are compatible with the predictions of the standard model of elementary particle physics. Much evidence points to the fact that the standard model is a low-energy approximation of a more comprehensive theory. Several of the standard model issues originate in the sector of Higgs boson physics. An order of magnitude larger number of Higgs bosons, expected to be examined over the next 15 years, will help deepen our understanding of this crucial sector.

EP.TH.1025The necessity of pre-operative investigations for elective surgical patients

Introduction

Patients admitted for elective surgeries tend to get quite a few investigations at pre assessment. Are these strictly necessary? Are there significant cost implications? National Institute for health and Care Excellence first issued guidance on routine preoperative tests for elective surgery in 2003.

Aims

To carry out an audit of pre-operative investigations of elective surgical patients at pre-admission. To determine level of unnecessary tests.

Results

Regarding correlation between ASA grades and over testing, grade 4 is the highest and grade 2 is the lowest in meeting standard guideline per ASA grade. Only 20% intermediate surgical cases meet the guideline whereas 30% of minor and 85% of major cases meet guideline per surgery grade respectively. Majority of unnecessary tests are carried out in minor and intermediate cases. Very few cases of missing tests. Only four tests that should have been taken as per the guideline weren’t done in the whole cohort. For all cases,57.4% of FBC,38.2% of U&Es, 48.5% ECG and 5.9% lung function tests carried out unnecessarily.

Conclusion

Generally we are over-testing patients at pre-assessment. This seems to be an issue with minor and intermediate cases, with majors generally doing better in fulfilling the guidelines. This may not be deliberate but coincidence as major surgeries call for more tests. Over-testing is more of an issue in lower (1-2) ASA grades in minor and intermediate surgeries. Under-testing is very rare. Using NICE’s estimated costs for each test, approximately £965.78 was spent in 1.5 months for tests which were not needed.

EP.FRI.1020 The necessity of colonoscopy to rule out colorectal malignancy after computerised tomography proven diagnosis of acute diverticulitis

Introduction

The current Royal College of Surgeons commissioning guideline on colonic diverticular disease suggests that patients should undergo endoscopic evaluation of the colonic lumen after an episode of computed tomography (CT) proven acute diverticulitis to rule out malignancy. The necessity of routine endoscopic assessment of CT proven diverticulitis remains debatable.

Aim

To establish whether routine endoscopic assessment should be carried out for patients after an episode of acute diverticulitis.

Method

Data was collected retrospectively from all patients diagnosed with acute diverticulitis on CT and who subsequently had follow up endoscopic assessment from January to July 2019.

Results

Total number of patients were 64.Median age of the cohort was 58.Of all patients, 48 had diagnosis of uncomplicated diverticulitis whereas 16 patients had diagnosis of complicated diverticulitis on CT scan. All patients had follow up colonoscopy after an acute attack with following findings: 2 patients had no pathology, 56 patients had diagnosis of only diverticulosis, 4 patients had both diverticulosis and polyps and 2 patients had bowel cancer. All 4 cases of polyps had benign pathology and uncomplicated diverticulitis on CT scan. Two bowel cancer patients, one had complicated diverticulitis with thickening of proximal sigmoid and the other patient had abnormal sigmoid colon suggestive of malignancy on CT scan.

Conclusion

Recent meta-analysis showed no difference between diverticulitis and normal population group in terms of risk of bowel cancer. Routine colonoscopy may not be appropriate in patients with acute uncomplicated diverticulitis but endoscopic assessment after an episode of complicated diverticulitis is necessary.

1274 Impact of Covid 19 on Urgent Suspicion of GI Cancer Referral in a District General Hospital

Aim

Endoscopy services across United Kingdom were affected significantly since March 2020 due to Covid-19 pandemic. Services were reduced and were more selective. We aim to compare the impact on duration between referral to colonoscopy and the detection rate of pathology between February (pre- Covid) and August (Covid impacted) 2020.

Method

Data was analysed from a prospectively maintained database of patients referred for colonoscopy to Royal Alexandra Hospital, Scotland. Patients underwent colonoscopy in month of February and August 2020 were included. Bowel screening patients were excluded. Positive findings included diverticulosis, colitis, polyp and adenocarcinoma. P value of &lt; 0.05 was considered significant.

Results

Total number of patients included was 97 (55 in February, 42 in August). Median age was 61 and 69 years, respectively. Mean duration from referral to colonoscopy were 4 weeks in February and 7 weeks in August. qFIT test were found raised in 50.9% in February and 57.1% in August with positive findings of 47.3% in February and 66.7% in August. 46.4% in February and 16.7% in August had raised qFIT but normal findings (p &lt; 0.05). Two high grade dysplasia polyps and two adenocarcinomas were identified in February, none found in August.

Conclusions

Covid-19 pandemic has disrupted the endoscopic services prolonging the duration from referral to colonoscopy. qFIT test is more heavily relied to prioritise urgent colonoscopies resulting in more positive findings on colonoscopy. Cancer detection rate has reduced which is a consistent finding as the UK national endoscopy study. Massive efforts are needed to restore endoscopy services.

1586 Systematic Review and Meta-analysis of Randomised Controlled Trials of Intra-operative Surgical Drainage in Oesophagectomy

Aim

Three surgical approaches to oesophagus have been described. Drain placement in oesophagectomy remains controversial and is associated with complications. The review evaluates the effectiveness of surgically placed drain after oesophagectomy.

Method

Main electronic databases were searched for studies reported clinical outcomes or effects of cervical (neck), transthoracic (chest) and transabdominal drain placement. The systematic review was conducted according to PRISMA guidelines and meta-analysis was analysed using fixed and random-effects models.

Results

There were only two randomised controlled trials to date. Neither of these approaches (drain versus no drain) has convincing benefits in any particular oesophagectomy approach in early detection of anastomotic leakage, pleural effusion, and chylothorax nor disadvantages associated with significant morbidity and mortality and prolonged hospital stay.

Conclusions

Surgical drain in oesophagectomy may not confer additional benefit and routine practice of placement is surgeons preferential. The results do not reach statistical significance. Further work is required.

The role of protein content on the steady and oscillatory shear rheology of model synovial fluids

Recent studies have debated the role of protein content on the bulk rheology of synovial fluid; in particular, it has been questioned if proteins aggregate or interact with hyaluronic acid in synovial fluid to enhance bulk rheology, or if observed effects were due to systematic measurement error caused by interfacial rheology, stemming from protein adsorption to the interface. Utilizing several techniques to ensure results reflect only bulk rheology, an examination of the role of bovine serum albumin and γ-globulin on model synovial fluid rheology has been undertaken. When interfacial rheology caused by protein adsorption to the interface is abrogated, the bulk rheology of a model synovial fluid composed of bovine serum albumin, γ-globulin, and hyaluronic acid is found to be dominated solely by the hyaluronic acid over a wide range of shear rates, strains and frequencies. These results show that the previously reported enhanced rheological properties of model synovial fluids are solely due to interfacial rheology and not from any type of protein aggregation/interaction in bulk solution.

Vermicomposting of Tea Factory Coal Ash: metal accumulation and metallothionein response in Eisenia fetida (Savigny) and Lampito mauritii (Kinberg)

Earthworms can accumulate heavy metals in their intestines to a great extent. Impact of feed materials and duration of metal exposure on natural activity of earthworms are rather unclear; this investigation therefore addresses the impact of metal rich Tea Factory Coal Ash (TFCA) on reproduction, composting and metal accumulation ability of Eisenia fetida and Lampito mauritii. Earthworm count and cocoon production increased significantly during vermicomposting. pH of the vermicomposted mixtures shifted toward neutrality, total organic C decreased substantially and total N enhanced significantly compared to composting. High heavy metal (Mn, Zn, Cu, As) accumulation was recorded in the intestine of both the earthworm species. Moreover, gradual increase in the metal-inducible metallothionein concentration indicated the causal mechanism of metal accumulation in these species. TFCA+cow dung (CD) (1:1) were most favorable feed mixture for E. fetida and TFCA+CD (1:2) were good for L. mauritii in regard to metal accumulation and compost quality.

Magnetic vortex based transistor operations

Transistors constitute the backbone of modern day electronics. Since their advent, researchers have been seeking ways to make smaller and more efficient transistors. Here, we demonstrate a sustained amplification of magnetic vortex core gyration in coupled two and three vortices by controlling their relative core polarities. This amplification is mediated by a cascade of antivortex solitons travelling through the dynamic stray field. We further demonstrated that the amplification can be controlled by switching the polarity of the middle vortex in a three vortex sequence and the gain can be controlled by the input signal amplitude. An attempt to show fan-out operation yielded gain for one of the symmetrically placed branches which can be reversed by switching the core polarity of all the vortices in the network. The above observations promote the magnetic vortices as suitable candidates to work as stable bipolar junction transistors (BJT).

Mixed Saturated−Unsaturated Alkyl-Chain Assemblies: Solid Solutions of Zinc Stearate and Zinc Oleate

The linear saturated stearic acid and the bent mono-unsaturated oleic acid do not mix and form solid solutions. However, the zinc salts of these acids can. From X-ray diffraction and DSC measurements we show that the layered zinc stearate and zinc oleate salts form a homogeneous solid solution at all composition ratios. The solid solutions exhibit a single melting endotherm, with the melting temperature varying linearly with composition but with the enthalpy change showing a minimum. By monitoring features in the infrared spectra that are characteristic of the global conformation of the hydrocarbon chain, and hence can distinguish between stearate and oleate chains, it is shown that solid solution formation is realized by the introduction of gauche defects in a fraction of the stearate chains that are then no longer linear. This fraction increases with oleate concentration. It has also been possible from the spectroscopic measurements to establish a quantitative relation between molecular conformational order and the thermodynamic enthalpy of melting of the solid solutions.

Melting of Saturated Fatty Acid Zinc Soaps

The melting of alkyl chains in the saturated fatty acid zinc soaps of different chain lengths, Zn(C(n)H(2n+1)COO)(2); n = 11, 13, 15, and 17, have been investigated by powder X-ray diffraction, differential scanning calorimetry, and vibrational spectroscopy. These compounds have a layer structure with the alkyl chains arranged as tilted bilayers and with all methylene chains adopting a planar, all-trans conformation at room temperature. The saturated fatty acid zinc soaps exhibit a single reversible melting transition with the associated enthalpy change varying linearly with alkyl chain length, but surprisingly, the melting temperature remaining constant. Melting is associated with changes in the conformation of the alkyl chains and in the nature of coordination of the fatty acid to zinc. By monitoring features in the infrared spectra that are characteristic of the global conformation of the alkyl chains, a quantitative relation between conformational disorder and melting is established. It is found that, irrespective of the alkyl chain length, melting occurs when 30% of the chains in the soap are disordered. These results highlight the universal nature of the melting of saturated fatty acid zinc soaps and provide a simple explanation for the observed phenomena.

Contrasting melting behavior of zinc stearate and zinc oleate

The influence of a double bond in the middle of an otherwise flexible hydrocarbon chain on the melting of such assemblies has been investigated by comparing the melting behavior of zinc stearate and zinc oleate. By monitoring features in the infrared spectra that are characteristic of the global conformation of the hydrocarbon chain, it is shown that the double bond effectively decouples the thermal evolution of conformational disorder in the chain segments on either side of the double bond and the melting of each of these segments in the assembly occurs as independent events.

Protective immune responses elicited in mice by immunization with formulations of poly(lactide-co-glycolide) microparticles

Parenteral administration of microparticle encapsulated DNA elicits immune responses to the encoded antigens. Experiments were performed to test whether the addition of certain lipophilic agents to such formulations enhanced the activity of a beta-galactosidase (beta-gal) DNA vaccine. Addition of either taurocholic acid (TA) or monomethoxy polyethylene-glycol-distearoylphosphatidylehanolamine (PEG-DSPE) increased the efficiency of DNA encapsulation. Immunization of mice with encapsulated DNA formulations containing either compound significantly increased the number of antibody positive responders over that achieved with non-lipid containing particles. Moreover, responding animals demonstrated trends towards higher antibody titers and increased T cell responses. Tumor protection against the CT26.CL25 tumor cell line was demonstrated with lipid and non-lipid containing formulations. These results are the first demonstration of protection obtained by parenteral administration of PLG encapsulated DNA vaccines.

Transport of viral proteins to the apical membranes and interaction of matrix protein with glycoproteins in the assembly of influenza viruses

Influenza virus assembly and morphogenesis require transport of viral components to the assembly site at the apical plasma membrane of polarized epithelial cells and interaction among the viral components. In this report we have discussed the apical determinants present in the transmembrane domain (TMD) of influenza virus hemagglutinin (HA) and neuraminidase (NA), and the interaction of M1 with influenza virus HA and NA. Earlier studies have shown that the NA and HA TMDs possess determinant(s) for apical sorting and raft-association (Kundu et al., 1996. J. Virol 70, 6508-6515; Lin et al., 1998. J. Cell Biol. 142, 51-57). Analysis of chimeric constructs between NA and TR (human transferring receptor) TMDs and the mutations in the NA and HA TMD sequences showed that the COOH terminus of the NA TMD and NH(2) terminus of the HA TMD encompassing the exoplasmic leaflet of the lipid bilayers were significantly involved in lipid raft-association and that apical determinants were not discrete sequences but rather dispersed within the TMD of HA and NA. These analyses also showed that although both signals for apical sorting and raft-association resided in the NA TMD, they were not identical and varied independently. Interactions of M1 protein with HA or NA, the influenza virus envelope glycoproteins, were investigated by TX-100 detergent treatment of membrane fractions and floatation in sucrose gradients. Results from these analyses showed that the interaction of M1 with mature HA and NA, which associated with the detergent-resistant lipid rafts caused an increased detergent-resistance of the membrane-bound M1 and that M1 interacted with HA and NA both in influenza virus-infected cells as well as in recombinant vaccinia virus-infected cells coexpressing M1 with HA and/or NA. Furthermore, both the cytoplasmic tail and the TMD of HA caused an increased detergent-resistance of the membrane-bound M1 supporting their interaction with M1. Immunofluorescence analysis by confocal microscopy also showed colocalization supporting the interaction of M1 with HA and NA at the cell surface and during exocytic transport both in influenza virus-infected cells as well as in coexpressing cells.

The effect of polymethylmethacrylate and acrysof intraocular lenses on the posterior capsule in patients with a large capsulorrhexis

PURPOSE

We have previously shown that patients who have a capsulorrhexis larger than the diameter of a polymethylmethacrylate (PMMA) intraocular lens (IOL) rapidly develop increased posterior capsule opacification (PCO), in effect, producing an example of enhanced PCO. This study focuses on the influence of AcrySof IOLs on this process.

METHODS

Phacoemulsification was performed on two groups of patients. The first consisted of 38 patients with a large capsulorrhexis of 6-7 mm who received a 5.5-mm PMMA IOL. The second group of 32 patients had identical surgery and a 5.5-mm MA30 AcrySof IOL was implanted. On days 1,14, 28, 90, 180, and 360, high resolution digitized retroillumination images were taken of the posterior capsule. The PCO area was measured by image analysis at 90, 180, and 360 days. Wrinkling of the posterior capsule was determined at 90 days, and the progression or regression of lens epithelial cell (LEC) proliferation was established by examination of serial images at 28 and 180 days.

RESULTS

At 90 days, 79% of the patients with PMMA IOLs had moderate to severe wrinkling of the posterior capsule, whereas the patients with AcrySof IOLs had none (P <.001). The percentage of PCO area was 69% for the PMMA IOLs and 24% for the AcrySof IOL group at 360 days (P <.0001). In the PMMA group, LEC progression occurred in 77%, LEC growth was stable in 15%, and LEC regression occurred in only 8%, compared to 69% of patients with AcrySof IOLs (P <.0001).

CONCLUSIONS

In patients with a rhexis larger than the IOL, AcrySof IOLs potentially can prevent capsular wrinkling and cause less PCO than a PMMA IOL with a similar rhexis size. The LEC regression occurs with AcrySof between 28 and 180 days. The reasons for this are discussed.

Analysis of the transmembrane domain of influenza virus neuraminidase, a type II transmembrane glycoprotein, for apical sorting and raft association

Influenza virus neuraminidase (NA), a type II transmembrane protein, is directly transported to the apical plasma membrane in polarized MDCK cells. Previously, it was shown that the transmembrane domain (TMD) of NA provides a determinant(s) for apical sorting and raft association (A. Kundu, R. T. Avalos, C. M. Sanderson, and D. P. Nayak, J. Virol. 70:6508-6515, 1996). In this report, we have analyzed the sequences in the NA TMD involved in apical transport and raft association by making chimeric TMDs from NA and human transferring receptor (TR) TMDs and by mutating the NA TMD sequences. Our results show that the COOH-terminal half of the NA TMD (amino acids [aa] 19 to 35) was significantly involved in raft association, as determined by Triton X-100 (TX-100) resistance. However, in addition, the highly conserved residues at the extreme NH(2) terminus of the NA TMD were also critical for TX-100 resistance. On the other hand, 19 residues (aa 9 to 27) at the NH(2) terminus of the NA TMD were sufficient for apical sorting. Amino acid residues 14 to 18 and 27 to 31 had the least effect on apical transport, whereas mutations in the amino acid residues 11 to 13, 23 to 26, and 32 to 35 resulted in altered polarity for the mutant proteins. These results indicated that multiple regions in the NA TMD were involved in apical transport. Furthermore, these results support the idea that the signals for apical sorting and raft association, although residing in the NA TMD, are not identical and vary independently and that the NA TMD also possesses an apical determinant(s) which can interact with apical sorting machineries outside the lipid raft.

Double-masked prospective ocular safety study of a lens epithelial cell antibody to prevent posterior capsule opacification

PURPOSE

To evaluate the intraocular safety of an immunoconjugate (MDX-RA) developed to prevent posterior capsule opacification (PCO) in human eyes.

SETTING

St. Thomas's Hospital Eye Department, London, United Kingdom.

METHODS

Twenty-six patients had phacoemulsification and implantation of an intraocular lens (IOL). All were randomly allocated at the end of surgery to receive a 0.1 mL placebo or 0.1 mL of the immunotoxin MDX-RA intracamerally. Two doses of the drug were tested: 8 patients with a low dose (50 units), 9 patients with a high dose (100 units), and 9 with placebo. Follow-up at days 1, 14, 30, 60, 90, and 180 consisted of visual acuity measured by the Early Treatment of Diabetic Retinopathy Study test, contrast sensitivity, aqueous flare, specular microscopy of the IOL's anterior surface, and corneal endothelial counts. The percentage area of PCO was measured from retroillumination images of the posterior capsule.

RESULTS

There was no decrease in corneal endothelial cell count in toxin-treated patients. Early postoperative flare, anterior chamber cell count, and corneal pachymetry were higher in toxin-treated patients. The median percentage area of PCO at 1 year was 32.0 in the placebo group, 3.8 in the low-dose group, and 7.4 in the high-dose group (P = .06).

CONCLUSION

This prospective, randomized, placebo-controlled trial confirmed that MDX-RA is safe for intraocular use and is of potential value for further clinical trials of the prevention of PCO.

Intracellular replication of choleraphage straight phi92

The broad host range choleraphage straight phi92 contains a linear double-stranded DNA molecule of 68 kilobase (kb) pairs with 3' overhang cohesive ends. Following infection with phage straight phi92, the host macromolecular synthesis is shut off within the first 5 min, and synthesis of phage-specific DNA is detectable after 7 min of infection. At early times during infection, phage DNA is replicated in circular form and the synthesis is membrane associated. The closed circular form serves as the precursor for the synthesis of the mature phage DNA which is eventually packaged into the phage head. Pulse labeling of ultraviolet-irradiated infected cells at different times during infection has allowed identification of about 30 phage-specific proteins of which 6 are structural proteins. These proteins appear during the infection cycle in two distinct phases, early and late. Eighteen early and 12 late proteins have been identified.

Relationship between intraocular lens biomaterials and posterior capsule opacification

PURPOSE

To determine whether posterior capsule opacification (PCO) is influenced by intraocular lens (IOL) material.

SETTING

A British teaching hospital eye department.

METHODS

Ninety eyes were prospectively randomized to receive a poly(methyl methacrylate) (PMMA), silicone, or AcrySof IOL. All lenses had 6.0 mm optics and PMMA haptics. A standardized surgical protocol was performed by a single surgeon using an extracapsular technique with capsulorhexis. Patients having surgical complications were excluded and all patients had standardized medication and follow-up. Posterior capsule opacification was assessed by a digital retroillumination camera using a dedicated software program based on the analysis of texture in the image and calculated as the percentage area of opacified capsule. Data were analyzed 2 years postoperatively.

RESULTS

There was a significant difference in percentage of PCO at 2 years among the three lens types (P < .0001). The AcrySof lenses were associated with less PCO (median 11.75%) than PMMA (43.65%) and silicone (33.50%) lenses (P < .001 and P = .025, respectively). The difference between PMMA and silicone lenses was not statistically significant.

CONCLUSION

Intraocular lenses made from AcrySof were associated with a significantly reduced degree of PCO.