438 research outputs found

    Field Instrumentation and Analysis of the Tuttle Creek Bridge

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    Fatigue cracking has been an extensive problem for many steel bridges designed prior to the identification of fatigue-prone details. Distortion in bridges coupled with stress concentrations within bridge components can eventually lead to crack initiation. The Tuttle Creek Bridge, built in 1962, has developed fatigue cracks like many older steel bridges. The structure is a 5,350 ft. long, plate-girder bridge with two girders supporting a non-composite concrete deck. The majority of the cracks on the bridge are found in the upper web-gap region, which lies between the vertical connection stiffener and the upper flange. Cracks also have occurred in the transverse welds attaching the lateral gusset plates to the lower flange. Both these crack types are believed to be caused by differential deflection of the two girders. In 1986, the bridge was retrofitted to prevent further cracking. Cracking, however, continued after the 1986 retrofit. In 2000, the Kansas Department of Transportation retained the services of the University of Kansas to investigate the fatigue cracking. Finite element models were created to estimate the stresses in the upper web-gap regions in order to determine a proper repair plan. The recommended repair scheme was to positively attach the connection stiffener to the upper flange, which was also successfully performed in similar web-gap repairs. The University of Kansas also was retained to perform two load tests on the bridge to investigate the effectiveness of the repair. The first load test, which this report entails, examined the stresses within the fatigued regions prior to retrofit. A second test will be conducted after the repairs have been performed. Measurements taken during both tests will be compared to determine the fatigue improvement within the structure. Also, information gathered during the first test will also provide insight to improving the finite element models. This report includes information about the Tuttle Creek Bridge and a summary of its structural deficiencies. Details of the gage installation and load testing are provided. Stresses induced by the truck loadings are presented in addition to the inferences from the measurements taken

    Upper Ordovician Strata of Southern Ohio-Indiana: Shales, Shell Beds, Storms, Sediment Starvation, and Cycles

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    The Cincinnatian Series (ca. 450 to 442 Ma) of the Cincinnati Arch features some of the most spectacular Ordovician fossils in the world. The rich faunas of bryozoans, brachiopods, molluscs, echinoderms, and trilobites are preserved as discrete shell-rich limestones, cyclically interbedded with sparsely fossiliferous shales and mudstones that may yield exceptionally preserved trilobites and crinoids. Similar successions of shell beds interbedded with mudstones are common components of Paleozoic successions. In such successions, the genesis of the highly concentrated shell beds is often attributed to storm-winnowing, but is this the whole story? This trip will offer an overview of the classic Cincinnatian Series, with ample opportunity for examining and collecting the rich fossil assemblages throughout much of the succession. Discussions will focus on the origin of interbedded mudstone-limestone cycles. We will emphasize depositional processes, particularly the role of intermittent siliciclastic sediment supply, carbonate (shell) production, and winnowing by storms and other high-energy events in a critical discussion of the storm-winnowing model

    Combinations of idelalisib with rituximab and/or bendamustine in patients with recurrent indolent non-Hodgkin lymphoma

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    Key Points Combining phosphatidylinositol-3-kinase δ inhibition with rituximab, bendamustine, or both is feasible and active in relapsed iNHL. The safety of novel combinations should be proven in phase 3 trials before adoption in clinical practice.</jats:p

    Timing of Intervention Affects Brain Electrical Activity in Children Exposed to Severe Psychosocial Neglect

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    Background: Early psychosocial deprivation has profound effects on brain activity in the young child. Previous reports have shown increased power in slow frequencies of the electroencephalogram (EEG), primarily in the theta band, and decreased power in higher alpha and beta band frequencies in infants and children who have experienced institutional care. Methodology/Principal Findings: We assessed the consequences of removing infants from institutions and placing them into a foster care intervention on brain electrical activity when children were 8 years of age. We found the intervention was successful for increasing high frequency EEG alpha power, with effects being most pronounced for children placed into foster care before 24 months of age. Conclusions/Significance: The dependence on age of placement for the effects observed on high frequency EEG alpha power suggests a sensitive period after which brain activity in the face of severe psychosocial deprivation is less amenabl

    Mass spectrometry-directed structure elucidation and total synthesis of ultra-long chain (O-acyl)-ω-hydroxy fatty acids

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    The (O-acyl)-ω-hydroxy FAs (OAHFAs) comprise an unusual lipid subclass present in the skin, vernix caseosa, and meibomian gland secretions. Although they are structurally related to the general class of FA esters of hydroxy FAs (FAHFAs), the ultra-long chain (30-34 carbons) and the putative -substitution of the backbone hydroxy FA suggest that OAHFAs have unique biochemistry. Complete structural elucidation of OAHFAs has been challenging because of their low abundance within complex lipid matrices. Furthermore, because these compounds occur as a mixture of closely related isomers, insufficient spectroscopic data have been obtained to guide structure confirmation by total synthesis. Here, we describe the full molecular structure of ultra-long chain OAHFAs extracted from human meibum by exploiting the gas-phase purification of lipids through multistage MS and novel multidimensional ion activation methods. The analysis elucidated sites of unsaturation, the stereochemical configuration of carbon-carbon double bonds, and ester linkage regiochemistry. Such isomer-resolved MS guided the first total synthesis of an ultra-long chain OAHFA, which, in turn, confirmed the structure of the most abundant OAHFA found in human meibum, OAHFA 50:2. The availability of a synthetic OAHFA opens new territory for future investigations into the unique biophysical and biochemical properties of these lipids

    An integrative framework for the appraisal of coloration in nature

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    The world in color presents a dazzling dimension of phenotypic variation. Biological interest in this variation has burgeoned, due to both increased means for quantifying spectral information and heightened appreciation for how animals view the world differently than humans. Effective study of color traits is challenged by how to best quantify visual perception in nonhuman species. This requires consideration of at least visual physiology but ultimately also the neural processes underlying perception. Our knowledge of color perception is founded largely on the principles gained from human psychophysics that have proven generalizable based on comparative studies in select animal models. Appreciation of these principles, their empirical foundation, and the reasonable limits to their applicability is crucial to reaching informed conclusions in color research. In this article, we seek a common intellectual basis for the study of color in nature. We first discuss the key perceptual principles, namely, retinal photoreception, sensory channels, opponent processing, color constancy, and receptor noise. We then draw on this basis to inform an analytical framework driven by the research question in relation to identifiable viewers and visual tasks of interest. Consideration of the limits to perceptual inference guides two primary decisions: first, whether a sensory-based approach is necessary and justified and, second, whether the visual task refers to perceptual distance or discriminability. We outline informed approaches in each situation and discuss key challenges for future progress, focusing particularly on how animals perceive color. Given that animal behavior serves as both the basic unit of psychophysics and the ultimate driver of color ecology/evolution, behavioral data are critical to reconciling knowledge across the schools of color research

    Late-time observations of SN2006gy: Still Going Strong

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    Owing to its extremely high luminosity and long duration, SN2006gy radiated more energy in visual light than any other known SN. Two hypotheses to explain its high luminosity -- that it was powered by shock interaction with CSM as implied by its Type IIn spectrum, or that it was fueled by radioactive decay from a large mass of 56Ni synthesized in a pair-instability SN -- predicted different late-time properties. Here we present observations of SN2006gy obtained more than a year after discovery. We were unable to detect it at visual wavelengths, but clear near-IR K and H-band detections show that it is still at least as luminous as the peak of a normal SN II. We also present spectra giving an upper limit to the late-time Ha luminosity of about 1e39 erg/s. Based on the weak late-time Ha, X-ray, and radio emission, combined with the difficulty of explaining the shift to IR wavelengths, we can rule out ongoing CSM interaction as the primary late-time power source. Instead, we propose that the evolution of SN2006gy is consistent with one of two possible scenarios: (1) A pair-instability SN plus modest CSM interaction, where the radioactive decay luminosity shifts to the IR because of dust formation. (2) An IR echo, where radiation emitted during peak luminosity heats a pre-existing dust shell at radii near 1 light year, requiring the progenitor star to have ejected another 10 Msun shell about 1500 yr before the SN.Comment: ApJ accepted. changes from prev version include more extensive discussion of IR echo and implications, and new Fig

    A Burkholderia pseudomallei Toxin Inhibits Helicase Activity of Translation Factor eIF4A

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    This is the author accepted manuscript. The final version is available from American Association for the Advancement of Science via the DOI in this record.The structure of BPSL1549, a protein of unknown function from Burkholderia pseudomallei, reveals a similarity to Escherichia coli cytotoxic necrotizing factor 1. We found that BPSL1549 acted as a potent cytotoxin against eukaryotic cells and was lethal when administered to mice. Expression levels of bpsl1549 correlate with conditions expected to promote or suppress pathogenicity. BPSL1549 promotes deamidation of glutamine-339 of the translation initiation factor eIF4A, abolishing its helicase activity and inhibiting translation. We propose to name BPSL1549 Burkholderia lethal factor 1

    Assessment of quality of care given to diabetic patients at Jimma University Specialized Hospital diabetes follow-up clinic, Jimma, Ethiopia

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    <p>Abstract</p> <p>Background</p> <p>Sub-Saharan Africa is currently enduring the heaviest global burden of diabetes and diabetes care in such resource poor countries is far below standards. This study aims to describe the gaps in the care of Ethiopian diabetic patients at Jimma University Specialized Hospital.</p> <p>Methods</p> <p>329 diabetic patients were selected as participants in the study, aged 15 years or greater, who have been active in follow-up for their diabetes for more than 1 year at the hospital. They were interviewed for their demographic characters and relevant clinical profiles. Their charts were simultaneously reviewed for characters related to diabetes and related morbidities. Descriptive statistics was used for most variables and Chi-square test, where necessary, was used to test the association among various variables. P-value of < 0.05 was used as statistical significance.</p> <p>Results</p> <p>Blood glucose determination was done for 98.5% of patients at each of the last three visits, but none ever had glycosylated haemoglobin results. The mean fasting blood sugar (FBS) level was 171.7 ± 63.6 mg/dl and 73.1% of patients had mean FBS levels above 130 mg/dl. Over 44% of patients have already been diagnosed to be hypertensive and 64.1% had mean systolic BP of > 130 and/or diastolic > 80 mmHg over the last three visits. Diabetes eye and neurologic evaluations were ever done for 42.9% and 9.4% of patients respectively. About 66% had urine test for albumin, but only 28.2% had renal function testing over the last 5 years. The rates for lipid test, electrocardiography, echocardiography, or ultrasound of the kidneys during the same time were < 5% for each. Diabetic neuropathy (25.0%) and retinopathy (23.1%) were the most common chronic complications documented among those evaluated for complications.</p> <p>Conclusions</p> <p>The overall aspects of diabetes care at the hospital were far below any recommended standards. Hence, urgent action to improve care for patients with diabetes is mandatory. Future studies examining patterns and prevalence of chronic complications using appropriate parameters is strongly recommended to see the true burden of diabetes.</p
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