224 research outputs found

    An elastic mixed-modes I and II fracture criterion using an artificial neural network database

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    Many thin structural elements such as various parts of fuselage, tubular supports in oil/gas off-shore platforms, etc may fail under the mixed-modes I and II fracture. Although there are a number of criteria for the mixed-modes I and II fracture, none of them are universally accepted and applied to practical problems. This is mainly due to lack of knowledge about the fracture toughness under various mode-mixity and rather complexity of the pertinent relationships. This paper proposes a new and relatively simple criterion for the mixed-modes I and II fracture that uses an artificial neural network database to obtain the pertinent fracture toughness. The application of the criterion is demonstrated by applying it to an example

    To Comply Software and IT System Development with Related Laws

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    . Accretion procedure of crimes and security breaches against the privacy of individual’s information and their maintenance information systems has cost huge amount of financial and other resources loose. Consequently governments take serious actions toward approving protective legislation against cyber crimes and it will be duty of software developers to adopt policies and measures to ensure that their designed systems are compatible with existing laws and their amendments. Since information technology and legislation are two quite distinct sciences, existence of a mechanism to do this adjustment and satisfy security and legal requirements of a designing software system is very essential. This paper is representing a framework that will help IT professionals to extract security requirements from relevant rules and use them in design of a system which is in accordance with those rules. It is giving brief discussion of the framework’s methodology and design of a simulating computer-aided system of this framework. It also reports the research progress and new discovered conclusions

    Case Study of Decoherence Times of Transmon Qubit

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    In the past two decades, one of the fascinating subjects in quantum physics has been quantum bits (qubits). Thanks to the superposition principle, the qubits can perform many calculations simultaneously, which will significantly increase the speed and capacity of the calculations. The time when a qubit lives in an excited state is called decoherence time. The decoherence time varies considerably depending on the qubit type and materials. Today, short decoherence times are one of the bottlenecks in implementing quantum computers based on superconducting qubits. In this research, the topology of the transmon qubit is investigated, and the decoherence time caused by noise, flux, and critical current noise is calculated by numerical method.Comment: 7 pages, 5 figure

    Online unit clustering in higher dimensions

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    We revisit the online Unit Clustering and Unit Covering problems in higher dimensions: Given a set of nn points in a metric space, that arrive one by one, Unit Clustering asks to partition the points into the minimum number of clusters (subsets) of diameter at most one; while Unit Covering asks to cover all points by the minimum number of balls of unit radius. In this paper, we work in Rd\mathbb{R}^d using the LL_\infty norm. We show that the competitive ratio of any online algorithm (deterministic or randomized) for Unit Clustering must depend on the dimension dd. We also give a randomized online algorithm with competitive ratio O(d2)O(d^2) for Unit Clustering}of integer points (i.e., points in Zd\mathbb{Z}^d, dNd\in \mathbb{N}, under LL_{\infty} norm). We show that the competitive ratio of any deterministic online algorithm for Unit Covering is at least 2d2^d. This ratio is the best possible, as it can be attained by a simple deterministic algorithm that assigns points to a predefined set of unit cubes. We complement these results with some additional lower bounds for related problems in higher dimensions.Comment: 15 pages, 4 figures. A preliminary version appeared in the Proceedings of the 15th Workshop on Approximation and Online Algorithms (WAOA 2017

    A double-blind, randomized comparison study between Zytux� vs MabThera® in treatment of CLL with FCR regimen: Non-inferiority clinical trial

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    Background: Chronic lymphocytic leukemia (CLL) is characterized by accumulation of B cells in blood, lymphoid tissues and bone marrow. Addition of rituximab to CLL chemotherapy regimens has been associated with improved survival. The aim of this study was to establish efficacy and safety of Zytux� in comparison to MabThera® in treatment of CLL. Materials and Methods: Seventy CLL patients who met the criteria for entering the study were randomized into two groups (35 patients in each group). Both groups received Fludarabine and Cyclophosphamide plus Rituximab as part of the FCR regimen. Group A was treated with Zytux�, and group B was treated with MabThera®. A non-inferiority margin of 20 for the primary outcome was defined to examine the similarity between Zytux� and MabThera®. Results: Baseline demographic characteristics showed no statistically significant difference between the two groups. The two treatment groups were comparable in terms of laboratory and clinical findings, cellular index changes and CD (5, 19, 20 and 23) counts during therapy cycles and at the end of the treatment period. Regarding safety results, Zytux� demonstrated a similar profile of adverse reactions in comparison to MabThera®. Moreover, the overall response rate was 88 and 89 for Zytux� and MabThera®, respectively (CI -0.17, 0.18). Conclusion: Results showed non-inferiority of Zytux� in terms of efficacy and adverse events as a biosimilar version of MabThera®. © 2018, Tehran University of Medical Sciences (TUMS). All rights reserved

    Apigenin as Tumor Suppressor in Cancers: Biotherapeutic Activity, Nanodelivery, and Mechanisms With Emphasis on Pancreatic Cancer

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    Pancreatic cancer is the most lethal malignancy of the gastrointestinal tract. Due to its propensity for early local and distant spread, affected patients possess extremely poor prognosis. Currently applied treatments are not effective enough to eradicate all cancer cells, and minimize their migration. Besides, these treatments are associated with adverse effects on normal cells and organs. These therapies are not able to increase the overall survival rate of patients; hence, finding novel adjuvants or alternatives is so essential. Up to now, medicinal herbs were utilized for therapeutic goals. Herbal-based medicine, as traditional biotherapeutics, were employed for cancer treatment. Of them, apigenin, as a bioactive flavonoid that possesses numerous biological properties (e.g., anti-inflammatory and anti-oxidant effects), has shown substantial anticancer activity. It seems that apigenin is capable of suppressing the proliferation of cancer cells via the induction of cell cycle arrest and apoptosis. Besides, apigenin inhibits metastasis via down-regulation of matrix metalloproteinases and the Akt signaling pathway. In pancreatic cancer cells, apigenin sensitizes cells in chemotherapy, and affects molecular pathways such as the hypoxia inducible factor (HIF), vascular endothelial growth factor (VEGF), and glucose transporter-1 (GLUT-1). Herein, the biotherapeutic activity of apigenin and its mechanisms toward cancer cells are presented in the current review to shed some light on anti-tumor activity of apigenin in different cancers, with an emphasis on pancreatic cancer. © Copyright © 2020 Ashrafizadeh, Bakhoda, Bahmanpour, Ilkhani, Zarrabi, Makvandi, Khan, Mazaheri, Darvish and Mirzaei

    A double-blind, randomized comparison study between Zytux� vs MabThera® in treatment of CLL with FCR regimen: Non-inferiority clinical trial

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    Background: Chronic lymphocytic leukemia (CLL) is characterized by accumulation of B cells in blood, lymphoid tissues and bone marrow. Addition of rituximab to CLL chemotherapy regimens has been associated with improved survival. The aim of this study was to establish efficacy and safety of Zytux� in comparison to MabThera® in treatment of CLL. Materials and Methods: Seventy CLL patients who met the criteria for entering the study were randomized into two groups (35 patients in each group). Both groups received Fludarabine and Cyclophosphamide plus Rituximab as part of the FCR regimen. Group A was treated with Zytux�, and group B was treated with MabThera®. A non-inferiority margin of 20 for the primary outcome was defined to examine the similarity between Zytux� and MabThera®. Results: Baseline demographic characteristics showed no statistically significant difference between the two groups. The two treatment groups were comparable in terms of laboratory and clinical findings, cellular index changes and CD (5, 19, 20 and 23) counts during therapy cycles and at the end of the treatment period. Regarding safety results, Zytux� demonstrated a similar profile of adverse reactions in comparison to MabThera®. Moreover, the overall response rate was 88 and 89 for Zytux� and MabThera®, respectively (CI -0.17, 0.18). Conclusion: Results showed non-inferiority of Zytux� in terms of efficacy and adverse events as a biosimilar version of MabThera®. © 2018, Tehran University of Medical Sciences (TUMS). All rights reserved

    Chitosan-based nanoscale systems for doxorubicin delivery:Exploring biomedical application in cancer therapy

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    Abstract Green chemistry has been a growing multidisciplinary field in recent years showing great promise in biomedical applications, especially for cancer therapy. Chitosan (CS) is an abundant biopolymer derived from chitin and is present in insects and fungi. This polysaccharide has favorable characteristics, including biocompatibility, biodegradability, and ease of modification by enzymes and chemicals. CS‐based nanoparticles (CS‐NPs) have shown potential in the treatment of cancer and other diseases, affording targeted delivery and overcoming drug resistance. The current review emphasizes on the application of CS‐NPs for the delivery of a chemotherapeutic agent, doxorubicin (DOX), in cancer therapy as they promote internalization of DOX in cancer cells and prevent the activity of P‐glycoprotein (P‐gp) to reverse drug resistance. These nanoarchitectures can provide co‐delivery of DOX with antitumor agents such as curcumin and cisplatin to induce synergistic cancer therapy. Furthermore, co‐loading of DOX with siRNA, shRNA, and miRNA can suppress tumor progression and provide chemosensitivity. Various nanostructures, including lipid‐, carbon‐, polymeric‐ and metal‐based nanoparticles, are modifiable with CS for DOX delivery, while functionalization of CS‐NPs with ligands such as hyaluronic acid promotes selectivity toward tumor cells and prevents DOX resistance. The CS‐NPs demonstrate high encapsulation efficiency and due to protonation of amine groups of CS, pH‐sensitive release of DOX can occur. Furthermore, redox‐ and light‐responsive CS‐NPs have been prepared for DOX delivery in cancer treatment. Leveraging these characteristics and in view of the biocompatibility of CS‐NPs, we expect to soon see significant progress towards clinical translation

    Prevalence of Cannabis Lifetime Use in Iranian High School and College Students: A Systematic Review, Meta-Analyses,and Meta-Regression

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    Cannabis is the most widely used substance in the world. This study aimed to estimate the prevalence of cannabis lifetime use (CLU) in high school and college students of Iran and also to determine factors related to changes in prevalence. A systematic review of literature on cannabis use in Iran was conducted according to MOOSE guideline. Domestic scientific databases, PubMed/Medline, ISI Web of Knowledge, and Google Scholar, relevant reference lists, and relevant journals were searched up to April, 2014. Prevalences were calculated using the variance stabilizing double arcsine transformation and confidence intervals (CIs) estimated using the Wilson method. Heterogeneity was assessed by Cochran's Q statistic and I-2 index and causes of heterogeneity were evaluated using meta-regression model. In electronic database search, 4,000 citations were retrieved, producing a total of 33 studies. CLU was reported with a random effects pooled prevalence of 4.0 (95 CI = 3.0 to 5.0). In subgroups of high school and college students, prevalences were 5.0 (95 CI = 3.0 to -7.0) and 2.0 (95 CI = 2.0 to -3.0), respectively. Meta-regression model indicated that prevalence is higher in college students (beta = 0.089, p < .001), male gender (beta = 0.017, p < .001), and is lower in studies with sampling versus census studies (beta = -0.096, p < .001). This study reported that prevalence of CLU in Iranian students are lower than industrialized countries. In addition, gender, level of education, and methods of sampling are highly associated with changes in the prevalence of CLU across provinces
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