Fluid Flow Regulates Articular Chondrocyte Mechanotransduction Pathways In 3D Culture

Mechanically compressing cartilage leads to fluid flow which regulates chondrocyte matrix metabolism. The mechanism through which this occurs is unclear, in part because of the coupled nature of physical stimuli associated with flow interactions with cartilage extracellular matrix as well as the lack of experimental techniques to directly quantify fluid flow through porous scaffolds used as tissue analogues. The objective of this research was to investigate the effects of physiologically relevant fluid flow on the metabolic response of chondrocytes cultured in threedimensional hydrogel scaffolds. The hypothesis of this research is that fluid flow regulates mechanotransduction of chondrocytes in 3-D alginate scaffolds through a calcium-mediated signaling pathway. In order to decouple the effects of the multiple stimuli associated with fluid flow the material properties of alginate hydrogels were characterized and used calculate the physical forces presented to cells via finite element models. The first aim developed a novel technique to visualize fluid flow in porous scaffolds in order to measure fluid velocity and generate flow profiles. The second aim examined the effects of fluid flow, particularly hydrostatic pressure and wall shear stress, on the calcium signaling response of chondrocytes seeded in alginate scaffolds. The third aim investigated the effects of cell-scaffold adhesion on chondrocyte calcium signaling response to fluid flow. These studies demonstrate that by directly measuring fluid flow through porous media and characterizing scaffold material properties, the physical stimuli presented to chondrocytes during perfusion can be calculated and correlated to metabolic response. Chondrocyte metabolism in three-dimensional alginate culture was dependent on the velocity of fluid rather than hydrostatic pressure or wall shear stress as previous monolayer studies have suggested. Additionally, this metabolic response was further modulated by chondrocyte attachment via integrins to the alginate substrate in a ligand density-dependent manner. This may indicate the involvement of focal adhesion complexes in mechanosensation of fluid flow. These findings indicate that the mechanism by which chondrocytes respond to fluid flow in vivo or in three-dimensional suspension culture is dependent on some combination of cell shape and surface attachment

Acoustic Emission Monitoring of Chemically Bonded Anchors

This paper presents a study on the use of acoustic emission (AE) to assess the structural soundness of concrete reinforced with chemically bonded anchors. The results of an experimental work based on six pullout tests monitored using an AE instrumentation suite are reported below. In every test one rebar was embedded in the hardened concrete by means of polyester resin. The AE was adopted to moni- tor the onset and progression of any structural damage. The parametric analysis, the intensity analysis and the moment tensor analysis of AE data were used to discriminate among different sources of damage. The technique shows promise for field application and may contribute to fully understand the structural mechanism in the rebar/adhesive/concrete sys- tems

A CAVERNOUS CRAM OF INFILL STRENGTH AND STIFFNESS FOR MULTI STOREY STRUCTURE

As reported by the code the posts and beams from the open ground floor should be created for 2.5 occasions the floor shears and moments calculated under seismic lots of bare frames. Therefore, the goal of this thesis is understood to be to determine the applicability from the multiplication factor of two.5 and also to read the aftereffect of infill strength and stiffness within the seismic analysis of low rise open ground floor building. Existence of infill walls within the frames alters the conduct from the building under lateral loads. However, it's quite common industry practice to disregard the stiffness of infill wall for analysis of presented building. Infill walls could be modeled in commercial software using two-dimensional area element with appropriate material qualities for straight line elastic analysis. Seismic look at a current reinforced concrete (RC) presented building would almost always need a non-straight line analysis. This building is examined for 2 different cases: (a) thinking about both infill mass and infill stiffness and (b) thinking about infill mass but without thinking about infill stiffness. Two separate models were generated using commercial software SAP2000. Two different support conditions, namely fixed finish support condition and pinned finish support condition, are thought to determine the aftereffect of support conditions within the multiplication factors. Straight line and non-straight line analyses were transported out for that models and also the outcome was compared. Nonlinear analysis reveals that open ground floor building fails via a ground floor mechanism in a comparatively low base shear and displacement and also the mode of failure is discovered to be brittle. Straight line and nonlinear analyses reveal that support condition influences the response significantly and could be an essential parameter to determine the pressure amplification factor

Association for Academic Surgery/Society of University Surgeons research awards are highly successful in fostering future surgeon-scientists.

BACKGROUND: The surgeon-scientist brings a unique perspective to surgical research. The Association of Academic Surgeons and Society of University Surgeons foster the development of surgeon-scientists through foundation awards to residents and junior faculty. We sought to evaluate the academic success of surgeons who received an Association for Academic Surgery/Society of University Surgeons award. METHODS: Information was collected for individuals who received a resident or junior faculty research award from the Association for Academic Surgery or Society of University Surgeons. Google Scholar, Scopus, and the National Institutes of Health Research Portfolio Online Reporting Tools: Expenditures and Results were used to assess scholarly achievements. RESULTS: Eighty-two resident awardees were included, 31 (38%) of whom were female. Thirteen (24%) are now professors, 12 (22%) are division chiefs, and 4 (7%) are department chairs. Resident awardees have a median of 886 citations (interquartile range 237-2,111) and an H-index of 14 (interquartile range 7-23). Seven (13%) went on to receive K08/K23 awards, and 7 (13%) received R01s, with a total of about $200 million in National Institutes of Health funding (79-fold return on investment). Thirty-four junior faculty awardees were included, 10 (29$139 million in National Institutes of Health funding (98-fold return on investment). CONCLUSION: Association for Academic Surgery/Society of University Surgeons research awardees experience high degrees of success in academic surgery. Most resident awardees pursue fellowship training and remain in academic surgery. A high percentage of both faculty and resident awardees hold leadership positions and successfully achieve National Institutes of Health funding

Detection and localization of debonding damage in composite-masonry strengthening systems with the acoustic emission technique

Different types of strengthening systems, based on fiber reinforced materials, are under investigation for external strengthening of historical masonry structures. A full characterization of the bond behavior and of the short—and long-term failure mechanisms is crucial to ensure effective design, compatibility and durability of the strengthening solution. In this paper, the effectiveness of the Acoustic Emission (AE) technique for debonding characterization and localization on Fiber Reinforced Polymer (FRP)- and Steel Reinforced Grout (SRG)-strengthened clay bricks is investigated. The AE technique proofs to be efficient for damage detection during accelerated ageing tests under thermal cycles and during experimental shear bond tests. AE data demonstrated the thermal incompatibility between brick and epoxy-bonded FRP composites during the accelerated ageing tests and debonding damage was successfully detected, characterized and located during the shear bond tests.- (undefined

A Novel Approach to Access the Quality of Tone Mapped Images

ABSTRACT: This paper deals with the assessment of measuring the quality of tone mapped images by considering the Tone Mapping Operators (TMOs) that convert high dynamic range (HDR) to low dynamic range (LDR) images provide practically useful tools for the visualization of HDR images on standard LDR displays. Different TMOs create different tone mapped images, and a natural question is which one has the best quality. Without an appropriate quality measure, different TMOs cannot be compared, and further improvement is directionless. Subjective rating may be a reliable evaluation method, but it is expensive and time consuming, and more importantly, is difficult to be embedded into optimization frameworks. Here we propose an objective quality assessment algorithm for tone mapped images by combining two concepts one of them is a multi scale signal fidelity measure on the basis of a modified structural similarity index and the other followed by a naturalness measure on the basis of intensity statistics of natural images. Validations using independent subject-rated image databases show good correlations between subjective ranking score and the proposed tone-mapped image quality index (TMQI). The proposed measure not only provides an overall quality score of an image, but also creates multi-scale quality maps that reflect the structural fidelity variations across scale and space. KEYWORDS: Tone Mapping Operators, low dynamic range, high dynamic range image, image fusion, image quality assessment, naturalness, perceptual image processing, structural similarity, tone mapping operator

Damage classification in reinforced concrete beam by acoustic emission signal analysis

Acoustic Emission (AE) is a non-destructive testing technique which can be used to identify both the damage level and the nature of that damage such as tensile cracks and shear movements at critical zones within a structure. In this work, the acoustic emission parameters of amplitude, rise time, average frequency and signal strength were used to classify the damage and to determine the damage level. Laboratory experiments were performed on a beam (150 x 250 x 1900 mm). The acoustic emission analysis was successfully used to determine crack movements and classify damage levels in accordance with the observations made during an increasing loading cycle

Environmental characterization and yield gap analysis to tackle genotype-by-environment-by-management interactions and map region-specific agronomic and breeding targets in groundnut

The high degree of Genotype by Environment by Management (GxExM) interactions is a serious challenge for production and crop improvement efforts. This challenge is especially true for a crop like groundnut that is often grown as a rainfed crop in diverse environments and management, leading to considerable production fluctuations among regions and seasons. Developing a means to characterize the drivers of variable yield and to identify region specific breeding objectives were the main motivations for this research, using groundnut production in India, as a case study for rainfed crops. Historically, five groundnut production areas have been considered by Indian crop improvement programs. Our objectives were to assess the relevance of this zonation system and possibly to re-define production areas with a higher degree of similarities into homogeneous production units (HPUs). Towards this, we used yield gap analysis and the geo-biophysical characters of the production region to understand and deal with GxExM interactions. Weather and soil data, crop parameters, and management information data were collected and groundnut production was simulated at the district scale over 30 consecutive years. Consequently, the geographic distribution of the potential yields and the yield gaps were first estimated to understand the main production limitations in a given region. Large and variable yield gaps (with a mean of ~70 %) were observed and results revealed a readily exploitable production gap (~ 8 M tons), which might be bridged by following recommended agronomic practices. Water deficit limited the yield potential by an average of 40 %, although with large variability among districts. However, large and variable yield gaps remained. To resolve the unexplained variation, principal component and cluster analysis of agronomic model output together with geo-biophysical indicators for each district were carried out. This resulted in seven HPUs, having well-defined production-limiting constraints. Grouping by HPU greatly reduced variance in actual and simulated yields, as compared to grouping across all groundnut production zones in India. The HPU based approach delimited precise geographic regions within which HPU-specific GxM products could be designed by crop improvement programs to boost productivity