Fatigue Behavior of High Strength Steel S890Q Containing Thermally Cut Straight Edges

This paper evaluates the effect of different thermal cutting methods on the fatigue life of high strength steel S890Q. The investigation covers flame, plasma and laser cutting methodologies, and specimens with rectangular sections and cut straight edges. The experimental program is composed of 30 specimens that were conducted to failure by applying fatigue cycles with a stress ratio (R) of 0.1 in a high frequency testing machine. The resultant best-fit S-N curves have been compared, revealing a better performance for laser cut straight edges. Moreover, the corresponding Eurocode 3 FAT class has been derived for each of the three cutting methods, resulting in FAT160 in all cases. This suggests that the use Eurocode 3 FAT125, which is the fatigue class currently provided for flame cut straight edges, is an overconservative assumption for thermally cut straight edges in steel S890Q, regardless of the thermal cutting technique being used (flame, laser or plasma)

Fatigue performance of thermally cut bolt holes in structural steel S460M

Current fatigue codes only consider the fatigue performance of drilled and punched holes, limiting the use of thermal cutting processes to produce bolt holes. This paper studies the fatigue performance of structural steel S460M plates containing thermally cut bolt holes. The research covers three thermal cutting methods: the traditional one (oxy-fuel cutting) and two more modern processes (plasma and laser cutting). Specimen geometry is defined by a rectangular cross section with a cut hole in the middle. All the specimens were conducted to failure by applying fatigue cycles, the stress ratio (R) being 0.1. The corresponding S-N curve and fatigue limit were obtained for each cutting method. Fatigue results have been compared with previous researches on fatigue performance of drilled and punched holes, and with the predictions provided by current fatigue standards, analyzing the possibility to extrapolate their S-N curves, focused on drilled and punched holes, to thermally cut holes

Multicentric myxoid liposarcoma: report of two cases

<p>Abstract</p> <p>Background</p> <p>Multicentric myxoid liposarcoma is a rather infrequent tumour that tends to behave aggressively.</p> <p>Case presentation</p> <p>We herein report two further cases of this tumour that have been managed in our Hospital. Both were young men with multiple sites of involvement at the moment of diagnosis and both have shown a bad prognosis with frequent recurrences after treatment and rapid death in one case.</p> <p>Conclusion</p> <p>We comment on the diagnosis of this entity and on the therapeutic options available for these patients.</p

Neuroinflammation and structural injury of the fetal ovine brain following intra-amniotic Candida albicans exposure.

BackgroundIntra-amniotic Candida albicans (C. Albicans) infection is associated with preterm birth and high morbidity and mortality rates. Survivors are prone to adverse neurodevelopmental outcomes. The mechanisms leading to these adverse neonatal brain outcomes remain largely unknown. To better understand the mechanisms underlying C. albicans-induced fetal brain injury, we studied immunological responses and structural changes of the fetal brain in a well-established translational ovine model of intra-amniotic C. albicans infection. In addition, we tested whether these potential adverse outcomes of the fetal brain were improved in utero by antifungal treatment with fluconazole.MethodsPregnant ewes received an intra-amniotic injection of 10(7) colony-forming units C. albicans or saline (controls) at 3 or 5 days before preterm delivery at 0.8 of gestation (term ~ 150 days). Fetal intra-amniotic/intra-peritoneal injections of fluconazole or saline (controls) were administered 2 days after C. albicans exposure. Post mortem analyses for fungal burden, peripheral immune activation, neuroinflammation, and white matter/neuronal injury were performed to determine the effects of intra-amniotic C. albicans and fluconazole treatment.ResultsIntra-amniotic exposure to C. albicans caused a severe systemic inflammatory response, illustrated by a robust increase of plasma interleukin-6 concentrations. Cerebrospinal fluid cultures were positive for C. albicans in the majority of the 3-day C. albicans-exposed animals whereas no positive cultures were present in the 5-day C. albicans-exposed and fluconazole-treated animals. Although C. albicans was not detected in the brain parenchyma, a neuroinflammatory response in the hippocampus and white matter was seen which was characterized by increased microglial and astrocyte activation. These neuroinflammatory changes were accompanied by structural white matter injury. Intra-amniotic fluconazole reduced fetal mortality but did not attenuate neuroinflammation and white matter injury.ConclusionsIntra-amniotic C. albicans exposure provoked acute systemic and neuroinflammatory responses with concomitant white matter injury. Fluconazole treatment prevented systemic inflammation without attenuating cerebral inflammation and injury

Mobile cm3-microrobots with tools for nanoscale imaging and micromanipulation

This paper presents a microrobot concept for microhandling and micromanipulation, which has been developed within the framework of the EU founded project MiCRoN. The concept is explained along with some examples of realized modules for the robots and a number of experimental results. The approach for the design of an individual robot is modular, with each module fulfilling a certain function. An overview is given on the system and robot concept, followed by a presentation of several modules for locomotion and tools. The tool modules include microgrippers as well as small scan stages for scanning probes based on piezoelectric monomorph elements. The overall size of the robots is projected to be about 1cm3. Each robot is individually configurable, which means that it can carry e.g. either a gripper, a scanner or other tools. A number of experiments with the robots have been carried out. Promising results were obtained with a number of already existing modules, showing the possibility to use a number of the presented robots for certain micromanipulation tasks, either individually or in cooperation with multiple agents

Position Feedback for Microrobots based on Scanning Probe Microscopy

A cluster of small cooperative robots capable of executing measurement and manipulation tasks is being developed within the scope of a European project. The robots are autonomous and have an overall dimension in the order of 1 cm/sup 3/. In this paper we present the concept of the robots, along with possible locomotion modules based on piezoelectric stick-slip actuators. Tools can be added to the robot for different measurements and manipulations. The integration of an AFM probe on the robot has been realized as a high resolution sensor for localization purposes and for measurements. First experimental results are shown

Pediatric Pedestrian Injuries: Striking Too Close to Home

Pediatric pedestrian injuries (PPI) are a major public health concern. This study utilized geospatial analysis to characterize the risk and injury severity of PPI. A retrospective chart review of PPI patients (age < 18) from a level 1 trauma center was performed (2013–2020). A geographic information system geocoded injury location to home and other public landmarks. Incidents were aggregated to zip codes and the Local Indicators of Spatial Association statistic tested for spatial clustering of injury rates per 10,000 children. Predictors for increased injury severity were assessed by logistic regression. PPI encompassed 6% (n = 188) of pediatric traumas. Most patients were black (54%), male (58%), >13 years (56%), and with Medicaid insurance (68%). Nine zip codes comprised a statistically significant cluster of PPI. Nearly half (40%) occurred within a quarter mile of home; 7% occurred at home. Most (65%) PPI occurred within 1 mile of a school, and 45% occurred within a quarter mile of a park. Nearly all (99%) PPI occurred within a quarter mile of a major intersection and/or roadway. Using admission to ICU as a marker for injury severity, farther distance from home (OR 1.060, 95% CI 1.001–1.121, p = 0.045) and age <13 years (3.662, 95% CI 1.854–7.231, p < 0.001) were independent predictors of injury severity. There are significant sociodemographic disparities in PPI. Most injuries occur near patients’ homes and other public landmarks. Multidisciplinary injury prevention collaboration can help inform policymakers, direct local safety programs, and provide a model for PPI prevention at the national level. Level IV. [Display omitted