EFFECT OF UNCERTAINTY ON THE FATIGUE RELIABILITY OF REINFORCED CONCRETE BRIDGE DECK UNDER HIGH STRESS LOADS

The deterioration of reinforced concrete bridge deck that has been damaged as a result of load action can affect the durability, safety and function of the structure. In this paper, a reliability time-variant fatigue analysis and uncertainty effect on the serviceability of reinforced concrete bridge deck was carried out. A simply supported 15m bridge deck was specifically used for the investigation. Mathematical models were developed and the uncertainties in structural resistance, applied loadings as well as the structural components were accommodated using probabilistic method. The limit state functions were evaluated using the First Order Reliability Algorithm and the entire process was implemented using a developed MATLAB program called Rayswit.m. Failure in the deck shear region gave the most critical effect with a reliability index range of 6.95 to -12.38 when compared to flexure region with an index of 8.58 to -10.53. http://dx.doi.org/10.4314/njt.v35i3.

Tuning the Hydrophobicity of Layer-Structure Silicates To Promote Adsorption of Nonaqueous Fluids: Effects of F– for OH– Substitution on CO2 Partitioning into Smectite Interlayers

The intercalation of non-aqueous fluids in the nanopores of organic and inorganic materials is of significant interest, particularly in the energy science community. Recently, XRD and computational modeling results have shown that structural F- for OH- substitution in layered silicates makes them more hydrophobic. Here, we use Grand Canonical Molecular Dynamics (GCMD) calculations to investigate how increasing the F-/(F-+OH-) ratio of a prototypical layered silicate (the smectite Na-hectorite) impacts the intercalation behavior of CO2 and H2O at elevated temperature and pressure. At the conditions of this study (T = 323 K, P = 90 bar, water-saturated CO2), increasing F- for OH- substitution causes decreasing total CO2+H2O intercalation, increasing CO2/(CO2+H2O) ratios in the interlayer galleries, and an increasing energy barrier to CO2 and H2O intercalation. CO2 intercalation is greatest at monolayer basal spacings, and the results support the idea that with Na+ as the exchangeable cation the interlayers must be propped open by some H2O molecules to allow CO2 to enter the interlayer galleries. The computed immersion energies suggest that the bilayer or a more expanded structure is the stable state under these conditions, in agreement with experimental results, and that the basal spacings of the minimum energy 2L structures increase with increasing F- for OH- substitution. These results are consistent with a wide range of experimental data for smectites at ambient conditions and elevated pressures and temperatures and suggest that F- for OH- substitution in conjunction with reduced structural charge and exchange with large, low charge cations may increase the ability of smectite minerals to incorporate hydrophobic species such as CH4, CO2, H2, and other organic compounds

Single Dose of Dexamethasone for Prevention of Nausea and Vomiting After Major Gynaecological Surgery

BACKGROUND: Post-operative nausea and vomiting (PONV) is a common complications following general anaesthesia and is a leading cause of morbidity following surgery . The mainstay of management them is by the use of antiemetic.METHOD: It was a randomized double blind placebo controlled study. The sample size was calculated as 90 from previous study with 10% attrition to make the 100. They were randomly divided into two groups; group Breceived dexamethasone prophylactically at induction while group A received placebo also at induction. All patients had balanced general anaesthesia and were taken to the recovery room postoperatively whereincidences of postoperative nausea and vomiting were recorded. Patients with incidences of nausea and vomiting were treated with 10mg metoclopramide intravenously while postoperative complications thatmay be associated with dexamethasone prophylaxis were also noted.RESULTS: The groups were comparable with respect to demographic characteristics. More patients in group A(placebo group)) had incidence of nausea than group B (dexamethasone group) with p value of 0.01 and also more patients in group A had vomiting than group B with p value of 0.02; which was significant. The duration of stay in the recovery room for both groups A and B were however comparable with no statistical difference.CONCLUSION: Dexamethasone when given prophylactically at induction reduces incidence of postoperative nausea and vomiting after  gynaecological surgeries.KEYWORDS: Postoperative nausea (PONV), Dexamethasone, prophylaxis, gynaecology

Antioxidant activities of Parquetina nigrescens

The antioxidant activities of different extracts (aqueous, methanol and flavonoid) of Parquetina nigrescens and butylated hydroxyl anisole, as reference compound, were evaluated in terms of scavenging effect, reducing power and inhibition of Fe2+/ascorbate-induced mitochondrial lipid peroxidation in rat liver. Extracts of P. nigrescens scavenged 2,2-diphenyl-1-picrylhydrazyl (DPPH) generated radicals in the increasing order of flavonoid > methanol > aqueous > BHA at 1000 g/ml. The reducing power followed a similar trend as observed with scavenging activities. Extracts of P. nigrescens, at 50 mg/ml, exhibited significant (P < 0.05) inhibitory effects on  Fe2+/ascorbate-induced lipid peroxidation in rat liver mitochondria. These results showed that P. nigrescens contains antioxidants that could be useful in attenuating reactions which generate free radicals in the body.Key words: Parquetina nigrescens, antioxidant activities, lipid peroxidation

Glycated hemoglobin and incident type 2 diabetes in singaporean Chinese adults: The Singapore Chinese Health Study

Background: The American Diabetes Association recently included glycated hemoglobin in the diagnostic criteria for diabetes, but research on the utility of this biomarker in Southeast Asians is scant. The aim of this study was to evaluate the association between percent HbA1c and incident diabetes in an Asian population of adult men and women without reported diabetes. Methods: Data analysis of 5,770 men and women enrolled in the Singapore Chinese Health Study who provided a blood sample at the follow-up I visit (1999-2004) and had no cancer and no reported history of diabetes or cardiovascular disease events. Diabetes was defined as self-report of physician diagnosis, identified at the follow-up II visit (2006-2010). Results: Hazard ratios (and 95%confidence intervals) for incident diabetes by 5 categories of HbA1c were estimated with Cox regression models and continuous HbA1c with cubic spline analysis. Compared to individuals with an HbA1c ≤ 5.7% (≤39 mmol/mol), individuals with HbA1c 5.8-5.9% (40-41 mmol/mol), 6.0-6.1% (42-43 mmol/mol), 6.2-6.4% (44-47 mmol/mol), and ≥ 6.5% (≥48 mmol/mol) had significantly increased risk for incident diabetes during followup. In cubic spline analysis, levels below 5.7% HbA1c were not significantly associated with incident diabetes. Conclusions: Our study found a strong and graded association with HbA1c 5.8% and above with incident diabetes in Chinese men and women

Magnetic and dielectric properties of multiferroic Eu0.5Ba0.25Sr0.25TiO3 ceramics

Dielectric and magnetic properties of Eu0.5Ba0.25Sr0.25TiO3 are investigated between 10 K and 300 K in the frequency range from 10 Hz to 100 THz. A peak in permittivity revealed near 130 K and observed ferroelectric hysteresis loops prove the ferroelectric order below thistemperature. The peak in permittivity is given mainly by softening of the lowest frequency polar phonon (soft mode revealed in THz and IR spectra) that demonstrates displacive character of the phase transition. Room-temperature X-ray diffraction analysis reveals cubic structure, but the IR reflectivity spectra give evidence of a lower crystal structure, presumably tetragonal I4/mcm with tilted oxygen octahedra as it has been observed in EuTiO3. The magnetic measurements show that the antiferromagnetic order occurs below 1.8 K. Eu0.5Ba0.25Sr0.25TiO3 has three times lower coercive field than Eu0.5Ba0.5TiO3, therefore we propose this system for measurements of electric dipole moment of electron.Comment: Phase Transitions, in pres

Safety of benzodiazepines and opioids in interstitial lung disease: A national prospective study

Copyright ©ERS 2018 Safety concerns are a barrier to prescribing benzodiazepines (BDZs) and opioids in interstitial lung disease (ILD). We therefore examined the association of BDZs and opioids on risk of admission to hospital and death. We conducted a population-based longitudinal cohort study of fibrotic ILD patients starting long-term oxygen therapy in Sweden between October 2005 and December 2014. Effects of BDZs and opioids on rates of admission to hospital and mortality were analysed using Fine-Gray and Cox regression while adjusting for potential confounders. We included 1603 patients (61% females). BDZs were used by 196 (12%) patients and opioids were used by 254 (15%) patients. There was no association between BDZs and increased admission. Treatment with high- versus low-dose BDZs was associated with increased mortality (subdistribution hazard ratio (SHR) 1.46, 95% CI 1.08-1.98 versus 1.13, 95% CI 0.92-1.38). Opioids showed no association with increased admission. Neither low-dose opioids (30 mg·day −1 oral morphine equivalent) (SHR 1.18, 95% CI 0.96-1.45) nor high-dose opioids (>30 mg·day −1 oral morphine equivalent) (SHR 1.11, 95% CI 0.89-1.39) showed association with increased mortality. This first ever study to examine associations between BDZ and opioid use and harm in ILD supports the use of opioids and low-dose BDZs in severely ill patients with respiratory compromise

Rotation of electromagnetic fields and the nature of optical angular momentum

The association of spin and orbital angular momenta of light with its polarization and helical phase fronts is now well established. The problems in linking this with electromagnetic theory, as expressed in Maxwell's equations, are rather less well known. We present a simple analysis of the problems involved in defining spin and orbital angular momenta for electromagnetic fields and discuss some of the remaining challenges. Crucial to our investigation is the duplex symmetry between the electric and magnetic fields

Acute osteomyelitis as cause of late sepsis in a Nigerian neonate

Neonatal osteomyelitis (NO) is said to be rare and uncommonly reported in the sub‑region. Although this may be true, either because the cases are under‑diagnosed, unreported or under‑reported. The diagnosis is clinical and supported with blood culture or the aspiration of pus with radiological findings. We report a case of a neonate with acute osteomyelitis of the right femur, diagnosed at 10th day of life, which was confirmed with blood culture and radiogram findings of the right upper thigh of the baby. To the best of our knowledge, this is the first documented reported case of NO from the south‑eastern Nigeria. It is imperative to recognize the clinical presentation necessary to raise the suspicion of NO and other focal infection in the newborn. With thorough examination and selected investigation the focus of infection in the neonate can be detected.Keywords: Neonatal, Nigeria, Osteomyelitis, Septicemi