Automated algorithm for impact force identification using cosine similarity searching

© 2018 A similarity searching technique is adopted to identify the impact force applied on a rectangular carbon fibre-epoxy honeycomb composite panel. The purpose of this study is to simultaneously identify both the location and magnitude of an unknown impact using the measured dynamic response collected by only a single piezoelectric sensor. The algorithm assumes that a set of impact forces are concurrently applied on a set of pre-defined locations. However, the magnitude of all the impact forces except one is considered to be zero. The impact force at all potential locations is then reconstructed through an l2-norm-based regularisation via two strategies: even-determined approach and under-determined approach. In an even-determined approach, the reconstruction process is performed independently for each pair of sensor and potential impact location. However, in an under-determined approach, the captured vibration signal is the superposition of the responses of the simultaneous ‘assumed’ impacts at the potential locations. Using either approach, a reconstructed impact force is obtained for each potential impact location. The reconstructed impact forces at spurious locations are expected to have zero magnitude as no impact has actually occurred at these locations. However, there might be some non-zero reconstructed impact forces at spurious locations. Therefore, it is worth designing an automated algorithm capable of detecting the most probable location. Cosine similarity searching is adopted to measure the intensity of the relationship between the reconstructed forces and an impact-like signal with various scale parameters. The largest value of cosine among all reconstructed forces corresponds to the most probable impact location. The results illustrate successful identification of the impact force location and magnitude for both even-determined and under-determined approaches

Automated Operational Modal Analysis of a Cable-Stayed Bridge

© 2017 American Society of Civil Engineers. Automated techniques for analyzing the dynamic behavior of full-scale civil structures are becoming increasingly important for continuous structural health-monitoring applications. This paper describes an experimental study aimed at the identification of modal parameters of a full-scale cable-stayed bridge from the collected output-only vibration data without the need for any user interactions. The work focuses on the development of an automated and robust operational modal analysis (OMA) algorithm, using a multistage clustering approach. The main contribution of the work is to discuss a comprehensive case study to demonstrate the reliability of a novel criterion aimed at defining the hierarchical clustering threshold to enable the accurate identification of a complete set of modal parameters. The proposed algorithm is demonstrated to work with any parametric system identification algorithm that uses the system order n as the sole parameter. In particular, the results from the covariance-driven stochastic subspace identification (SSI-Cov) methods are presented

Combined use of platelet-rich plasma and adipose tissue-derived mesenchymal stem cells shows a synergistic effect in experimental spinal cord injury

Spinal cord injury (SCI) as a crippling disability causes tissue degeneration via neuron loss and fiber disruption. Some researchers have tried to reverse or minimize these changes. Platelet-rich plasma (PRP) is a biological product derived from peripheral blood containing a variety of growth factors. PRP has been extensively used in regenerative medicine. On the other hand, via secreting neuroprotective growth factors, mesenchymal stem cells (MSCs) have shown a promising potential in repairing central nervous system deficits. This study investigated the therapeutic effect of the combined use of MSCs and PRP in a rat model of SCI. We used real time-PCR method for evaluation of Bcl-2, Bax and caspase 3 expressions, TUNEL test for apoptotic cell death assessment, and neurofilament NF200 immunohistochemistry for examination of axonal regeneration. The results showed that co-treatment with MSCs and PRP efficiently alleviated the evaluated categories. Significant differences were observed in expression of Bcl-2 and caspase3, but not Bax, apoptotic index and the number of NF200 positive axons (for all P </= 0.01) between co-treatment animals compared with those treated with only MSCs or PRP. In conclusion, this study showed that combination of MSCs and PRP synergistically promotes their therapeutic effects in the SCI

Application of Queuing Analytic Theory to Decrease Waiting Times in Emergency Department: Does it Make Sense?

Background: Patients who receive care in an emergency department (ED), are usually unattended while waiting in queues. Objectives: This study was done to determine, whether the application of queuing theory analysis might shorten the waiting times of patients admitted to emergency wards. Patients and Methods: This was an operational study to use queuing theory analysis in the ED. In the first phase, a field study was conducted to delineate the performance of the ED and enter the data obtained into simulator software. In the second phase, "ARENA" software was used for modeling, analysis, creating a simulation and improving the movement of patients in the ED. Validity of the model was confirmed through comparison of the results with the real data using the same instrument. The third phase of the study concerned modeling in order to assess the effect of various operational strategies, on the queue waiting time of patients who were receiving care in the ED. Results: In the first phase, it was shown that 47.7% of the 3000 patient records were cases referred for trauma treatment, and the remaining 52.3% were referred for non-trauma services. A total of 56% of the cases were male and 44% female. Maximum input was 4.5 patients per hour and the minimum input was 0.5 per hour. The average length of stay for patients in the trauma section was three hours, while for the non-trauma section it was four hours. In the second phase, modeling was tested with common scenarios. In the third phase, the scenario with the addition of one or more senior emergency resident(s) on each shift resulted in a decreased length of stay from 4 to 3.75 hours. Moreover, the addition of one bed to the Intensive Care Unit (ICU) and/or Critical Care Unit (CCU) in the study hospital, reduced the occupancy rate of the nursing service from 76% to 67%. By adding another clerk to take electrocardiograms (ECG) in the ED, the average time from a request to performing the procedure is reduced from 26 to 18 minutes. Furthermore, the addition of 50% more staff to the laboratory and specialist consultations led to a 90 minute reduction in the length of stay. It was also shown that earlier consultations had no effect on the length of stay. Conclusions: Application of queuing theory analysis can improve movement and reduce the waiting times of patients in bottlenecks within the ED throughput

Convexity-Increasing Morphs of Planar Graphs

We study the problem of convexifying drawings of planar graphs. Given any planar straight-line drawing of an internally 3-connected graph, we show how to morph the drawing to one with strictly convex faces while maintaining planarity at all times. Our morph is convexity-increasing, meaning that once an angle is convex, it remains convex. We give an efficient algorithm that constructs such a morph as a composition of a linear number of steps where each step either moves vertices along horizontal lines or moves vertices along vertical lines. Moreover, we show that a linear number of steps is worst-case optimal. To obtain our result, we use a well-known technique by Hong and Nagamochi for finding redrawings with convex faces while preserving y-coordinates. Using a variant of Tutte's graph drawing algorithm, we obtain a new proof of Hong and Nagamochi's result which comes with a better running time. This is of independent interest, as Hong and Nagamochi's technique serves as a building block in existing morphing algorithms.Comment: Preliminary version in Proc. WG 201

Upward Planar Morphs

We prove that, given two topologically-equivalent upward planar straight-line drawings of an $n$-vertex directed graph $G$, there always exists a morph between them such that all the intermediate drawings of the morph are upward planar and straight-line. Such a morph consists of $O(1)$ morphing steps if $G$ is a reduced planar $st$-graph, $O(n)$ morphing steps if $G$ is a planar $st$-graph, $O(n)$ morphing steps if $G$ is a reduced upward planar graph, and $O(n^2)$ morphing steps if $G$ is a general upward planar graph. Further, we show that $\Omega(n)$ morphing steps might be necessary for an upward planar morph between two topologically-equivalent upward planar straight-line drawings of an $n$-vertex path.Comment: Appears in the Proceedings of the 26th International Symposium on Graph Drawing and Network Visualization (GD 2018) The current version is the extended on

Risk factors for delayed graft function in deceased donor kidney transplantation; A potential preventive role for intraoperative thymoglobulin

Introduction: Delayed graft function (DGF) is associated with significant adverse outcomes in deceased donor kidney transplantation (KT) including lower graft survival. However, risk factors and potential preventive strategies like intraoperative rabbit antithymocyte globulin (rATG; thymoglobulin) have not yet been fully evaluated. Objectives: The aim of this study was to investigate DGF risk factors and determine the association of intraoperative rATG with the risk of DGF in deceased donor kidney recipients. Patients and Methods: We retrospectively examined medical records of 163 first time deceased donor kidney transplant recipients at two major kidney transplant centers from 2014 to 2016. All the donors were standard heart-beating, brain death donors. Risk factors for DGF in recipients were evaluated using multivariate logistic regression analysis. Results: The mean recipients' age was 43±13 years and the majority of participants were male (64). The overall rate of DGF was 27. Intraoperative rATG was significantly associated with a lower rate of DGF (adjusted odds ratio AOR, 0.33, 95% CI, 0.11-0.95). Intraoperative transfusion (AOR, 3.7, 95% CI, 1.4-9.9) and diabetes mellitus (AOR, 3.7, 95% CI, 1.5-8.9) were significantly associated with higher risk of DGF. Conclusion: This study showed that intraoperative blood transfusion and diabetes mellitus were associated with increased risk of DGF. Meanwhile, administration of intraoperative rATG was associated with reduced odds ratio of DGF. Future studies are needed to evaluate the potential role of rATG in DGF-related renal outcomes. © 2019 The Author(s)

In vitro assessment of the combined effect of eicosapentaenoic acid, green tea extract and curcumin C3 on protein loss in C2C12 myotubes

EPA has been clinically shown to reduce muscle wasting during cancer cachexia. This study investigates whether curcumin or green tea extract (GTE) enhances the ability of low doses of eicosapentaenoic acid (EPA) to reduce loss of muscle protein in an in vitro model. A low dose of EPA with minimal anti-cachectic activity was chosen to evaluate any potential synergistic effect with curcumin or GTE. Depression of protein synthesis and increase in degradation was determined in C2C12 myotubes in response to tumour necrosis factor-α (TNF-α) and proteolysis-inducing factor (PIF). EPA (50 μM) or curcumin (10 μg ml−1) alone had little effect on protein degradation caused by PIF but the combination produced complete inhibition, as did the combination with GTE (10 μg ml−1). In response to TNF-α (25 ng ml−1)-induced protein degradation, EPA had a small, but not significant effect on protein degradation; however, when curcumin and GTE were combined with EPA, the effect was enhanced. EPA completely attenuated the depression of protein synthesis caused by TNF-α, but not that caused by PIF. The combination of EPA with curcumin produced a significant increase in protein synthesis to both agents. GTE alone or in combination with EPA had no effect on the depression of protein synthesis by TNF-α, but did significantly increase protein synthesis in PIF-treated cells. Both TNF-α and PIF significantly reduced myotube diameter from 17 to 13 μm for TNF-α (23.5%) and 15 μm (11.8%) for PIF However the triple combination of EPA, curcumin and GTE returned diameters to values not significantly different from the control. These results suggest that either curcumin or GTE or the combination could enhance the anti-catabolic effect of EPA on lean body mass