Resource
2020 EN
Ameer R. K. Nassrah · István Jánossy · Tibor Tóth-Katona
The influence of the molecular structure of the nematic liquid crystal (NLC)on the photoalignment process at the NLC -- polymer interface has beeninvestigated experimentally. NLCs having exclusively phenyl-, or cyclohexanerings in the rigid core, as well as NLCs containing both phenyl and cyclohexanegroups have been considered. Substantial differences have been found in thephotoalignment process depending on the molecular structure of the NLC,supporting the assumption that the polymer -- NLC interface should be regardedas a coupled system, where the two components mutually influence each other. Aphenomenological explanation is given for the observed differences.
Resource
2020 EN
Safwa Ameer · Matt Gibson-Lopez · Erik Krohn
+2 more
In this paper, we consider the Visibility Graph Recognition andReconstruction problems in the context of terrains. Here, we are given a graph$G$ with labeled vertices $v_0, v_1, \ldots, v_{n-1}$ such that the labelingcorresponds with a Hamiltonian path $H$. $G$ also may contain other edges. Weare interested in determining if there is a terrain $T$ with vertices $p_0,p_1, \ldots, p_{n-1}$ such that $G$ is the visibility graph of $T$ and theboundary of $T$ corresponds with $H$. $G$ is said to be persistent if and onlyif it satisfies the so-called X-property and Bar-property. It is known thatevery "pseudo-terrain" has a persistent visibility graph and that everypersistent graph is the visibility graph for some pseudo-terrain. Theconnection is not as clear for (geometric) terrains. It is known that thevisibility graph of any terrain $T$ is persistent, but it has been unclearwhether every persistent graph $G$ has a terrain $T$ such that $G$ is thevisibility graph of $T$. There actually have been several papers that claimthis to be the case (although no formal proof has ever been published), andrecent works made steps towards building a terrain reconstruction algorithm forany persistent graph. In this paper, we show that there exists a persistentgraph $G$ that is not the visibility graph for any terrain $T$. This meanspersistence is not enough by itself to characterize the visibility graphs ofterrains, and implies that pseudo-terrains are not stretchable.
Resource
2020 EN
Amruthlal M · Devika S · Ameer Suhail P A
+8 more
Patients who undergo mechanical heart valve replacements or have conditionslike Atrial Fibrillation have to take Vitamin K Antagonists (VKA) drugs toprevent coagulation of blood. These drugs have narrow therapeutic range andneed to be very closely monitored due to life threatening side effects. Thedosage of VKA drug is determined and revised by a physician based onProthrombin Time - International Normalised Ratio (PT-INR) value obtainedthrough a blood test. Our work aimed at predicting the maintenance dosage ofwarfarin, the present most widely recommended anticoagulant drug, using thede-identified medical data collected from 109 patients from Kerala. A SupportVector Machine (SVM) Regression model was built to predict the maintenancedosage of warfarin, for patients who have been undergoing treatment from aphysician and have reached stable INR values between 2.0 and 4.0.
Resource
2020 EN
Ameer Haj-Ali · Hasan Genc · Qijing Huang
+4 more
We explore applying the Monte Carlo Tree Search (MCTS) algorithm in anotoriously difficult task: tuning programs for high-performance deep learningand image processing. We build our framework on top of Halide and show thatMCTS can outperform the state-of-the-art beam-search algorithm. Unlike beamsearch, which is guided by greedy intermediate performance comparisons betweenpartial and less meaningful schedules, MCTS compares complete schedules andlooks ahead before making any intermediate scheduling decision. We furtherexplore modifications to the standard MCTS algorithm as well as combining realexecution time measurements with the cost model. Our results show that MCTS canoutperform beam search on a suite of 16 real benchmarks.
Journals
2020 EN
Mushtaq Abdul Kareem Hussein · Abdul Kareem F. Hassan · Najim Abdul Ameer Saad.
This paper aims to design and construct of an automated device for testing the scratch resistance of the polymeric materials by measuring the force required to cause a scratch on the surface of polymeric materials as well as calculating the friction coefficient from the input and output of the device. The device was made of materials available in the local market and some parts were manufactured in local mechanical workshops. The device consists of four main parts were mechanical parts, scratching mechanism parts, electrical and electronic parts and the device operating program. The device designed in this work has the following specifications: normal load (0.1 N - 325 N), sliding speed (1 mm/s - 35 mm/s), tangential force measured by the load cell (0.1 N to 294 N), the samples dimensions (length: 10 - 195 mm, width: 10 - 125 mm, and thickness: 0.25 - 50 mm), maximum scratch length of 195 mm, and the height of the indenter from the platform surface (0.25 mm to 50 mm). Scratch test and calculation of the friction coefficient were performed for samples of pure and reinforced PMMA by Silicon Oxide nanoparticles (SiO2). The results showed an increase in scratch resistance and a decrease in the friction coefficient with increasing the weight ratio of SiO2. Also, the ability of the designed device to measure the tangential force required for scratching accurately and quickly and in simple steps.
Journals
2019 EN
Israa Abdul Ameer AbdulJabbar · Zainab Ali Yakoob.
This paper present a hybrid technique between two of the most popular face recognition methods, Principal Component Analysis (PCA) and singular value decomposition (SVD), and attempts to offer a study for all its mathematical equations in detail and concentrate on the hybrid place between equations in order to focus on the way of processing the hybrid method. Dot product used in mathematical equations and for testing the proposed method used Olivetti Research Laboratory (ORL) data set images were used with different number of images for training set and used various number of Eigen faces and used also dissimilar number for test images and Manhattan distance was used to measure the distances between image vectors in this system, the result shows that the recognition rate using this hybrid technique is higher than the recognition rate using PCA or SVD separately and each time increase the threshold value the accuracy rate increased and conclude that when increase the threshold value and the chosen number of Eigen faces then recognition rate increased.
Journals
2019 EN
Amrou Sarraj · Ameer E Hassan · Sean I. Savitz
+18 more
The efficacy and safety of endovascular thrombectomy (EVT) in patients with large ischemic cores remains unknown, to our knowledge.
American Medical Association
Journals
2019 EN
Saleh Ameer L. · Obed Adel A. · AlYasir Yasir I. A.
+4 more
Summary Recently, a new scheme of conventional PID (Proportional Integral Derivative) controller has been utilized in different electrical drives for speed control. This paper presents an optimal P I λ D μ controller with 2DOF and anti‐windup techniques based on PSO optimization to produce the proposed controller which is exploited in order to control the velocity control of LIM. A three‐phase inverter with SVPWM technique that is depended on approach of IFOC method is exploited to obtain the necessary output voltage supplied to the main windings of the LIM in order to control the velocity with minimum harmonics and good characteristics. The end effect is taken into account in dq axis equivalent circuit. Computed investigations show that the proposed controller is efficient in improving motor performance.
Journals
2019 EN
Wang Xinlong · RiveraBolanos Nancy · Jiang Bin
+1 more
Stem cell–based therapies can potentially regenerate many types of tissues and organs, thereby providing solutions to a variety of diseases and injuries. However, acute cell death, uncontrolled differentiation, and low functional engraftment yields remain critical obstacles for clinical translation. Advanced functional biomaterial scaffolds that can deliver stem cells to the targeted tissues/organs and promote stem cell survival, differentiation, and integration to host tissues may potentially transform the clinical outcome of stem cell–based regenerative therapies. In this review, the authors briefly summarize sources of stem cells for transplantation, present the current state of the art in biomaterial design for stem cell delivery, and provide critical analysis for existing materials. Applications to the cardiovascular, neural, and musculoskeletal systems are highlighted with recent nonclinical studies and clinical trials. The authors also discuss how advances in biomaterials research can contribute to regenerative medicine research and stem cell therapies.
Journals
2019 EN
Tom Abbott · Kathryn Greaves · A Patel
+2569 more
Background The Clavien–Dindo classification is perhaps the most widely used approach for reporting postoperative complications in clinical trials. This system classifies complication severity by the treatment provided. However, it is unclear whether the Clavien–Dindo system can be used internationally in studies across differing healthcare systems in high‐ (HICs) and low‐ and middle‐income countries (LMICs). Methods This was a secondary analysis of the International Surgical Outcomes Study (ISOS), a prospective observational cohort study of elective surgery in adults. Data collection occurred over a 7‐day period. Severity of complications was graded using Clavien–Dindo and the simpler ISOS grading (mild, moderate or severe, based on guided investigator judgement). Severity grading was compared using the intraclass correlation coefficient (ICC). Data are presented as frequencies and ICC values (with 95 per cent c.i.). The analysis was stratified by income status of the country, comparing HICs with LMICs. Results A total of 44 814 patients were recruited from 474 hospitals in 27 countries (19 HICs and 8 LMICs). Some 7508 patients (16·8 per cent) experienced at least one postoperative complication, equivalent to 11 664 complications in total. Using the ISOS classification, 5504 of 11 664 complications (47·2 per cent) were graded as mild, 4244 (36·4 per cent) as moderate and 1916 (16·4 per cent) as severe. Using Clavien–Dindo, 6781 of 11 664 complications (58·1 per cent) were graded as I or II, 1740 (14·9 per cent) as III, 2408 (20·6 per cent) as IV and 735 (6·3 per cent) as V. Agreement between classification systems was poor overall (ICC 0·41, 95 per cent c.i. 0·20 to 0·55), and in LMICs (ICC 0·23, 0·05 to 0·38) and HICs (ICC 0·46, 0·25 to 0·59). Conclusion Caution is recommended when using a treatment approach to grade complications in global surgery studies, as this may introduce bias unintentionally.