11,815 research outputs found

    A Dimension-Adaptive Multi-Index Monte Carlo Method Applied to a Model of a Heat Exchanger

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    We present an adaptive version of the Multi-Index Monte Carlo method, introduced by Haji-Ali, Nobile and Tempone (2016), for simulating PDEs with coefficients that are random fields. A classical technique for sampling from these random fields is the Karhunen-Lo\`eve expansion. Our adaptive algorithm is based on the adaptive algorithm used in sparse grid cubature as introduced by Gerstner and Griebel (2003), and automatically chooses the number of terms needed in this expansion, as well as the required spatial discretizations of the PDE model. We apply the method to a simplified model of a heat exchanger with random insulator material, where the stochastic characteristics are modeled as a lognormal random field, and we show consistent computational savings

    Magec: An image searching tool for detecting forged images in forensic investigation

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    © 2016 IEEE. Manipulation of digital images for the purpose of forgery is a rapidly growing phenomenon that poses a challenge for cyber-crime investigators. Distinguishing original images from duplicates and the number of original copies within the same media are some examples of challenges presented by duplicate digital images. In this paper, we present a new image-searching tool called, Magec, to detect duplicate image(s) on digital media, using the original image modification attributes as a signature. First, we describe the tool and the methods used to detect duplicate images, then we evaluate the tool\u27s performance based on the number of folders it searches and the number of files it searches for. Later, we present the analysis of the tool using different operating system attributes. The goal is to find copies of the same object that is hidden; compressed images, or images saved with different attributes and demonstrates which one is the original image and thereby deduce which ones are copies. This research helps in better utilization of small/limited capacity devices, where limited storage capacity may be a problem. The experimental results prove that the presented search tool provides faster and accurate results. Finally, the conducted tests on the Magec tool analyzed, and verified, and the results are presented alongside with challenges identified

    New insight into single phase formation of capric acid/menthol eutectic mixtures by Fourier-transform infrared spectroscopy and differential scanning calorimetry

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    Purpose: To examine the structural changes of a eutectic mixture comprising capric acid and menthol which are commonly used in pharmaceutical applications. Methods: A phase diagram was constructed by quantitative mixing of capric acid and menthol under controlled conditions until a single liquid phase was formed. Eutectic mixtures of capric acid: menthol at the ratios of 3:2, 1:4, 1:1, 2:3, and 1:4 were prepared. Hydrogen bond formation and conformational changes were analyzed using Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Microscopic imaging was carried out to capture phase change events upon increasing temperature. Results: Menthol confirmed the intact structure of a hexagonal ring. The high degree of broadening of the menthol O-H groups indicates hydrogen bond formation. FTIR band changes related to capric acid suggest a break-up of the methylene arrangement structure due to changes in the C-H band frequencies. The red shift encountered in C=O stretching band emphasizes hydrogen bond formation taking place between the oxygen atom of the hydroxyl group comprising the carboxylic moiety of capric acid and the hydrogen atom of menthol hydroxyl group. DSC results indicate the presence of two polymorphs of the capric acid/ menthol complex. Both exhibited crystallization and conformational change exotherms in addition to two melting endotherms as result of transformation of crystalline components to become partially crystalline due to hydrogen bond formation. Conclusion: The interaction between capric acid and menthol results in a typical preparation of deep eutectic systems that can act as natural-based solvents in numerous pharmaceutical applications. Keywords: Eutectic system, Capric acid, Menthol, Differential scanning calorimetry, DSC, Fourier transform infrared spectroscopy, FTI

    Symmetric encryption relying on chaotic henon system for secure hardware-friendly wireless communication of implantable medical systems

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    Healthcare remote devices are recognized as a promising technology for treating health related issues. Among them are the wireless Implantable Medical Devices (IMDs): These electronic devices are manufactured to treat, monitor, support or replace defected vital organs while being implanted in the human body. Thus, they play a critical role in healing and even saving lives. Current IMDs research trends concentrate on their medical reliability. However, deploying wireless technology in such applications without considering security measures may offer adversaries an easy way to compromise them. With the aim to secure these devices, we explore a new scheme that creates symmetric encryption keys to encrypt the wireless communication portion. We will rely on chaotic systems to obtain a synchronized Pseudo-Random key. The latter will be generated separately in the system in such a way that avoids a wireless key exchange, thus protecting patients from the key theft. Once the key is defined, a simple encryption system that we propose in this paper will be used. We analyze the performance of this system from a cryptographic point of view to ensure that it offers a better safety and protection for patients. 2018 by the authors.Acknowledgments: This publication was made possible by NPRP grant #8-408-2-172 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.Scopu

    Evaluation of meat and meat product oxidation and off-flavor formation: Managing oxidative changes

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    One of the primary issues with processed foods during heat treatment and freezing storage is fat oxidation, which causes significant changes in fats due to their interaction with reactive oxygen species (ROS). This interaction leads to the creation of various aldehydes that have a high affinity for large molecules, such as proteins, leading to the formation of final products of advanced oxidation processes that contribute to food spoilage. Co-oxidation can also result in extensive damage. Another problem affecting the quality and nutritional value of meat products is protein oxidation, which can occur during storage via freezing and thawing or as a result of heat treatment. Heat treatment can cause physical and chemical changes, such as the loss of some essential amino acids and the transformation of certain amino acids into carbonyl compounds via various mechanisms. Protein oxidation is indicated by the accumulation of these carbonyl compounds, and the heat treatment can lead to the denaturation of myoglobin, which is responsible for the brown color of cooked meat and is influenced by several factors. Active protein aggregates can interact with the oxidation products of polyunsaturated fatty acids and with carbohydrate glycation or glycoxidation to produce Maillard products. It is critical to understand the oxidative changes that occur in fats and proteins in food, particularly in meat products, since these components are among the primary constituents of food.One of the primary issues with processed foods during heat treatment and freezing storage is fat oxidation, which causes significant changes in fats due to their interaction with reactive oxygen species (ROS). This interaction leads to the creation of various aldehydes that have a high affinity for large molecules, such as proteins, leading to the formation of final products of advanced oxidation processes that contribute to food spoilage. Co-oxidation can also result in extensive damage. Another problem affecting the quality and nutritional value of meat products is protein oxidation, which can occur during storage via freezing and thawing or as a result of heat treatment. Heat treatment can cause physical and chemical changes, such as the loss of some essential amino acids and the transformation of certain amino acids into carbonyl compounds via various mechanisms. Protein oxidation is indicated by the accumulation of these carbonyl compounds, and the heat treatment can lead to the denaturation of myoglobin, which is responsible for the brown color of cooked meat and is influenced by several factors. Active protein aggregates can interact with the oxidation products of polyunsaturated fatty acids and with carbohydrate glycation or glycoxidation to produce Maillard products. It is critical to understand the oxidative changes that occur in fats and proteins in food, particularly in meat products, since these components are among the primary constituents of food

    Information Security Risk Assessment Methods in Cloud Computing: Comprehensive Review

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    Cloud computing faces more security threats, requiring better security measures. This paper examines the various classification and categorization schemes for cloud computing security issues, including the widely known CIA trinity (confidentiality, integrity, and availability), by considering critical aspects of the cloud, such as service models, deployment models, and involved parties. A comprehensive comparison of cloud security classifications constructs an exhaustive taxonomy. ISO27005, NIST SP 800–30, CRAMM, CORAS, OCTAVE Allegro, and COBIT 5 are rigorously compared based on their applicability, adaptability, and suitability within a cloud-based hosting methodology. The findings of this research recommend OCTAVE Allegro as the preferred cloud hosting paradigm. With many security models available in management studies, it is imperative to identify those suitable for the rapidly expanding and dynamically evolving cloud environment. This study underscores the significant methods for securing data on cloud-hosting platforms, thereby contributing to establishing a robust cloud security taxonomy and hosting methodology

    Factorization and Nonfactorization in B Decays

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    Using NLL values for Wilson coefficients and including the contributions from the penguin diagrams, we estimate the amount of nonfactorization in two-body hadronic B decays. Also, we investigate the model dependence of the nonfactorization parameters by performing the calculation using different models for the form factors. The results support the universality of nonfactorizable contributions in both Cabibbo-favored and Cabibbo-suppressed B decays.Comment: 17 pages, 5 figures, revte

    The Role of Ki-67 Immunoexpression in Diagnosis of Molar Pregnancy and Differentiating its Subtypes

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    الهدف:-  لدراسة دور التعبير المناعي ل Ki-67  في تشخيص الحمل العنقودي وتمييزها عن الانواع الأخرى لأنواع اجهاض الحمل. العمليات:- ثمان وستون نموذج لنواتج الحمل المثبتة بالفورمالين والمطمورة بالفورمالين ، والتي شملت أجهاض الحمل في الأشهر الأولى (15 نموذج)، حمل عنقودي جزئي ( 24 نموذج)، حمل عنقودي كامل ( 24 نموذج)  ومشيمة الحمل الكامل  (5 نموذج). جميع النماذج تم جمعها من مختبرات فحص الأنسجة  في مستشفى الولادة في اربيل / العراق خلال الفترة من ايلول 2012- ايلول 2013. تم استخدام التصبيغ المناعي الهيستوكيمياوي ل Ki-67 وباستعمال المضاد الأحادي MIB-1 وباستخدام الطريقة المعتادة . المؤشر التعريفي لKi-67 (عدد الأنوية المصبوغة/عدد الأنوية الكلي) لكل من الزغابات المشيمة  والجذعة الغذائية الخلوية والجذعة الغذائية المخلاوية والخلايا السدوية تم حسابها بصورة منفصلة. الحسابات الأحصائية تم اجراءها بأستخدام مؤشر Fisher  واذا كانت قيمة الp أقل من 0.05 تم اعتباره ذو قيمة أحصائية. النتائج:-  أظهرت الدراسة أن مؤشر ال Ki-67 في كل امراض الزغابات المشيمية كان عالي وبصورة خاصة في الزغابات المشيمية للحمل العنقودي الكامل  (>50%  ) ثم في الحمل العنقودي الجزئي (>20%). كذلك تم ايجاد علاقة ذو قيمة احصائية  للتعبير المناعي لل Ki-67  والتي كانت مفيدة في التمييز بين الأجهاض والحمل العنقودي الكامل ( p<0.01) والحمل العنقودي الجزئي ( p<0.05). الأستنتاج:- المؤشر التعريفي ل Ki-67  في الزغابات المشيمية كان ذو قيمة في تشخيص وتمييز الحمل العنقودي من الأجهاض في الأشهر الأولى للحمل وكذلك في تمييز الحمل العنقودي الكامل من الحمل العنقودي الجزئي .Objectives: The study is intended to evaluate the role of Ki-67 immunoexpression in the diagnosis of molar pregnancy & differential diagnosis of its subgroups from miscarriage. Methods: Sixty eight formalin-fixed, paraffin- embedded specimens of products of conception , including 1st trimester miscarriage (n=15), partial hydatidiform mole PHM (n=24), complete hydatidiform CHM (n=24) and full term placenta (n=5), all were examined at Histopathology Department of Maternity Teaching Hospital in Erbil, Iraq during the period Sep.2012-Sep.2013. Ki-67 immunohistochemical staining was performed by using the monoclonal antibody MIB-1 and the standard streptavidin-biotin immunoperoxidase method. The labeling index (number of positive nuclei/total number of nuclei) for villous, cytotrophoblasts , syncytiotrophoblasts and stromal cells were evaluated separately. Statistical analysis was carried out by Fisher’s exact test & statistical significance was determined at p < 0.05. Results: The study shows that all villous trophoblastic lesions showed high Ki-67 in all villous components especially cytotrophoblasts, being the highest in CHM mole(>50%) followed by PHM (>20%). Also found a statistically significant differences in immunoexpressins of Ki-67 that was useful in separating miscarriage from CHM, p<0.01 (highly significant), and partial hydatidiform mole p<0.05, (significant). Conclusion: Ki-67 labeling index of villous cells ,especially cytotrophoblasts, is valuable in diagnosis and differentiation of hydatidiform mole from 1st trimester miscarriage as well as between different subgroups of hydatidiformmoles (CHM & PHM)

    Multiwall carbon nanotube reinforced HA/HDPE biocomposite for bone reconstruction

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    The healing of bone fractures naturally occurs without surgical intervention. Some damage and fractures in bone tissue are complex and leave remnant deformation, and this requires the use of bone replacement material. Hydroxyapatite (HA) is the main element of the bone mineral form and consider as a bioactive material which supports bone growth. Nevertheless, the HA has poor mechanical properties, such as low tensile strength. Thus the applications in bone replacement have been limited, especially in high load-bearing applications. A Carbone nanotube has newly obtained considerable concern because of their mechanical properties, potentially enhancing the bone implant's clinical efficiency. This study attempted to explain the effect of adding Multi-walled carbon nanotubes MWCNT Nanoparticles to the HDPE/HA bio-composites. Two groups of the composites samples were produced 20HA/80 HDPE and 40 HA/ 60 HDPE with adding (0.6, 1, 1.4, 2) % weights of (MWCNT) to each group. The composites were fabricated using a hot pressing technique with various pressing pressures (29, 57, 86, and 114 Mpa) at a compounding temperature of 150 C° and a holding time of 15 minutes. To evaluate samples' characteristics and performance, X-ray powder diffraction (XRD), surface topography by Field Emission Scanning Electron Microscopy (FE-SEM), tensile strength and, microhardness test were investigated. The results showed that the hybrid bio-composites demonstrated excellent structural integrity, homogeneous with the fibrous structure, and improved mechanical properties. When increasing in MWNT additions and increasing hot-press pressure, enhancing the composites' fracture strength and microhardness is beneficial. The excellent properties of hybrids bio-composite (HA/HDPE/MWCNT) samples for homogeneous fibrous structure and high mechanical properties could be applied in bone tissue engineering for bone reconstruction

    Incidence and contributing factors of glucose intolerance in Saudi postpartum women: Sub-group analysis from RAHMA study

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    Objectives: The objectives of this study were to determine incidence and risk factors of glucose intolerance one year after delivery in a sub-cohort of Riyadh Mother and Baby Cohort Study (RAHMA) study. Methods: This is a follow-up study of a sub-cohort from RAHMA study from King Khalid University Hospital (KKUH). All women from RAHMA database who completed one year since delivery at KKUH were contacted by phone to participate in the study. Previously collected data from RAHMA registry for each participant were linked to this study data. Clinical data measured for each participant included current weight and height to calculate the BMI and waist circumference. Blood tests done for each participant were fasting blood glucose (FPG) and HbA1c. Based on the blood tests results, participants were classified into three groups; diabetic, pre-diabetic and normal. The incidence of diabetes and prediabetes was calculated for the whole cohort. Clinical, biochemical, and sociodemographic predictors of glucose intolerance were compared between the three groups. Risk factors with P-value less than 0.05 were tested in multivariate regression model with bootstrapping to calculate the relative risk (RR) and its 95% Bias corrected Confidence Interval (C.I.) Results: From the sub-cohort, 407 women fulfilled the inclusion criteria and agreed to participate in the study. From the study participants; 250 (61.4%) women were normoglycemic, 142 (35%) women had prediabetes and 15 (3.6%) women were diabetic. Following multivariable regression analysis only history of gestational diabetes mellitus (GDM), (RR 1.74, 95% CI (1.06 to 2.84), P = 0.01), obesity (RR 1.69, 95% CI (1.01–3.11), P = 0.04) and diastolic blood pressure, (RR 1.04, 95% CI (1.01–1.09), P = 0.03) remained as predictors of postpartum glucose intolerance. Conclusion: The incidence of postpartum glucose intolerance (diabetes and prediabetes) is very high in Saudi women. Both GDM and obesity are strong predictors of glucose intolerance
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