323 research outputs found
Behaviour of R.C. beams upgraded with externally bonded steel or FRP plates
The structural behaviour of simply supported reinforced concrete (R.C.) beams
strengthened in flexure by externally bonded steel or fibre reinforced plastic (FRP)
plates has been investigated. A novel theoretical model coupled with simple (hence,
practical) procedure(s) for designing such beams against premature plate peeling failure
has been developed. The theoretical model and the design procedures have been
validated by an extensive number (169) of mainly large-scale test data (using steel or
FRP plates) from other sources. The effects of variations in the magnitude of Young's
modulus for FRP plates on the potential changes in the flexural ultimate load of R. C.
beams with externally bonded FRP plates, in the absence and/or presence of plate
peeling, have been investigated in some detail with the theoretical predictions of
various failure loads and associated modes of failure supported by an extensive number
of test results from other sources. Moreover, brief theoretical parametric studies for
other first order composite beam design parameters have also been carried out in order
to clarify the effects of variations in such parameters on the predicted modes of failure.
It has been shown (both, theoretically and by using large scale experimental data) that
the load bearing capacity for a plated beam could (under certain circumstances) be
significantly lower than even that for the corresponding unplated beam with the mode
of failure being of an undesirable brittle nature. Such brittle failures can obviously have
serious implications in practice, where this method has been used extensively for
upgrading both bridges and buildings in a number of countries, with the design
calculations very often not having properly accounted for the possible occurrence of
premature plate peeling phenomenon, especially when FRP plates have been used.
Further work in this area included a quantitative theoretical insight into the effect of
pre-cracking of the beams (under service conditions) on the ultimate plate peeling load.
A critical quantitative examination of a number of previously available theoretical
models, as proposed by others, has also been carried out, and some of these models for
predicting the plate peeling failure of R. C. beams have been shown to suffer from
rather serious shortcomings
Rheumatic tricuspid valve disease: Repair versus Replacement
Background: Tricuspid valve disease is most commonly functional, however, organic affection still accounts for one fourth of cases. Rheumatic fever which is endemic in Egypt is a main cause of organic affection. Current practice largely relies on tricuspid valve repair; however, it has been difficult to determine optimal procedure.
Objectives: Herein, we study the outcome of replacement versus repair in such patients.
Patients and methods: A prospective study was conducted on 300 consecutive patients with rheumatic heart disease showing severe tricuspid valve affection underwent tricuspid valve surgery, between 2014 and 2018. The patients were divided into two groups; TVR group (n=150) which included patients who underwent tricuspid valve replacement and TVr group (n=150) which included patients who underwent tricuspid valve repair. Diagnosis and follow up were done by echocardiography. Peri-operative variables, clinical outcome, morbidity, mortality, and follow up data were recorded.
Results: Mean follow-up was 4¹1.32 years. In-hospital mortality was 6 patients (4%) in TVR group and 3 patients (2%) in TVr group (P value ⼠0.05). Postoperative low cardiac output syndrome and stroke were significantly higher in the repair group. Postoperative RV dysfunction, renal impairment, renal failure and chest re-exploration were significantly higher in the replacement group. Severe tricuspid regurgitation was reported in 19 patients (12.6%) of the repair group on follow up.
Conclusion: Tricuspid valve repair is preferable to replacement to avoid the drawbacks of prosthesis. However, tricuspid valve replacement is feasible with comparable survival outcome and the progressive nature of the rheumatic disease may recommend replacement
Interleukin-17 and matrix metalloprotease-9 expression in the mycetoma granuloma
Mycetoma is a persistent, progressive granulomatous inflammatory disease caused either by fungi or by bacteria. Characteristic of this disease is that the causative agents organise themselves in macroscopic structures called grains. These grains are surrounded by a massive inflammatory reaction. The processes leading to this host tissue reaction and the immunophenotypic characteristics of the mycetoma granuloma are not known. Due to the massive immune reaction and the tissue remodeling involved, we hypothesised that the expression levels of interleukin-17 (IL-17) and matrix metalloprotease-9 (MMP-9) in the mycetoma granuloma formation were correlated to the severity of the disease and that this correlation was independent of the causative agent responsible for the granuloma reaction. To determine the expression of IL-17 and MMP-9 in mycetoma lesions, the present study was conducted at the Mycetoma Research Centre, Sudan. Surgical biopsies from 100 patients with confirmed mycetoma were obtained, and IL-17 and MMP-9 expression in the mycetoma granuloma were evaluated immunohistochemically. IL-17 was mainly expressed in Zones I and II, and far less in Zone III. MMP-9 was detected mainly in Zones II and III, and the least expression was in Zone I. MMP-9 was more highly expressed in Actinomadura pelletierii and Streptomyces somaliensis biopsies compared to Madurella mycetomatis biopsies. MMP-9 levels were directly proportional to the levels of IL-17 (p = 0.001). The only significant association between MMP9 and the patients' characteristics was the disease duration (
Change in prescription pattern as a potential marker for adverse drug reactions of angiotensin converting enzyme inhibitors
Background Angiotensin converting enzyme inhibitors (ACEIs) are among the most frequently prescribed groups of medications. ACEI-induced adverse drug reactions (ADRs) are the main reason to discontinue or switch ACEI treatment. ADRs information is not available in prescription databases. Objective To identify a proxy for ACEI-induced ADRs in prescription databases. Setting The Rotterdam Study is an ongoing prospective cohort study that started in 1990 in the Netherlands and has included 14,926 subjects aged 45 years or older. Methods All ACEI starters from 2000 to 2011 were identified using prescription data within the Rotterdam Study. Participants were classified into 4 mutually exclusive groups: continuing, discontinuing, switching to angiotensin receptor blockers (ARBs), and switching to other antihypertensives. For categorization, the maximum time-interval between two prescription periods was set at 3 and 6 months. Subsequently, primary care physician files were searched and clinical events were classified as definite ADRs, probable ADRs, possible ADRs and definite non-ADRs. Finally the accuracy of different prescription patterns as indicators of ADRs was evaluated. Main outcome measure Positive predictive values (PPVs), negative predictive values (NPVs), sensitivity and specificity of the prescription patterns of the 4 groups were calculated. Results Totally, 1132 ACEI starters were included. The PPV for a definite ADR was 56.1 % for switchers to ARB, while the PPVs for switchers to other antihypertensives, and discontinuation were 39.5 and 19.5 %, respectively. After including probable ADRs and possible ADRs, PPVs for switchers to ARB increased to 68.3 and 90.5 %. A 6-month interval gave slightly higher PPVs compared to a 3-month interval (maximum 6.1 % higher). The differences in NPVs between 3 and 6-months interval groups were approximately 1.0 %. Conclusions Switching ACEIs to ARBs is the best marker for ACEI-induced ADRs in prescription databases
First molecular analysis of rabies virus in Qatar and clinical cases imported into Qatar, a case report
Identifying the origin of the rabies virus (RABV) infection may have significant implications for control measures. Here, we identified the source of a RABV infection of two Nepalese migrants in Qatar by comparing their RABV genomes with RABV genomes isolated from the brains of a RABV infected camel and fox from Qatar
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV
The Lambda(b) differential production cross section and the cross section
ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum
pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7
TeV using data collected by the CMS experiment at the LHC. The measurements are
based on Lambda(b) decays reconstructed in the exclusive final state J/Psi
Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and
Lambda to proton pion, using a data sample corresponding to an integrated
luminosity of 1.9 inverse femtobarns. The product of the cross section times
the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls
faster than that of b mesons. The measured value of the cross section times the
branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06
+/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for
anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are
statistical and systematic, respectively.Comment: Submitted to Physics Letters
Measurement of isolated photon production in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV
Isolated photon production is measured in proton-proton and lead-lead
collisions at nucleon-nucleon centre-of-mass energies of 2.76 TeV in the
pseudorapidity range |eta|<1.44 and transverse energies ET between 20 and 80
GeV with the CMS detector at the LHC. The measured ET spectra are found to be
in good agreement with next-to-leading-order perturbative QCD predictions. The
ratio of PbPb to pp isolated photon ET-differential yields, scaled by the
number of incoherent nucleon-nucleon collisions, is consistent with unity for
all PbPb reaction centralities.Comment: Submitted to Physics Letters
Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV
A search is presented for physics beyond the standard model (BSM) in final
states with a pair of opposite-sign isolated leptons accompanied by jets and
missing transverse energy. The search uses LHC data recorded at a
center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to
an integrated luminosity of approximately 5 inverse femtobarns. Two
complementary search strategies are employed. The first probes models with a
specific dilepton production mechanism that leads to a characteristic kinematic
edge in the dilepton mass distribution. The second strategy probes models of
dilepton production with heavy, colored objects that decay to final states
including invisible particles, leading to very large hadronic activity and
missing transverse energy. No evidence for an event yield in excess of the
standard model expectations is found. Upper limits on the BSM contributions to
the signal regions are deduced from the results, which are used to exclude a
region of the parameter space of the constrained minimal supersymmetric
extension of the standard model. Additional information related to detector
efficiencies and response is provided to allow testing specific models of BSM
physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO
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