90 research outputs found

    Printed document integrity verification using barcode

    Get PDF
    Printed documents are still relevant in our daily life and information in it must be protected from threats and attacks such as forgery, falsification or unauthorized modification. Such threats make the document lose its integrity and authenticity. There are several techniques that have been proposed and used to ensure authenticity and originality of printed documents. But some of the techniques are not suitable for public use due to its complexity, hard to obtain special materials to secure the document and expensive. This paper discuss several techniques for printed document security such as watermarking and barcode as well as the usability of two dimensional barcode in document authentication and data compression with the barcode. A conceptual solution that are simple and efficient to secure the integrity and document sender's authenticity is proposed that uses two dimensional barcode to carry integrity and authenticity information in the document. The information stored in the barcode contains digital signature that provides sender's authenticity and hash value that can ensure the integrity of the printed document

    Low dose tranexamic acid effect on post-coronary artery bypass grafting bleeding

    Get PDF
    Objective: This study investigated the effects of low-dose tranexamic acid on post-coronary artery bypass surgery bleeding. Background: Diffuse microvascular bleeding is still a common problem after cardiac procedures. This study was designed to evaluate the hemostatic effects of low-dose tranexamic acid in on-pump coronary artery bypass graft surgery. Methods: In this prospective randomized placebo-controlled study, 150 patients who were candidates for coronary artery bypass were enrolled and randomly assigned to 1 of 2 groups (tranexamic acid or placebo). Total drainage volume and the need for transfusion as well as surgical complications were recorded and compared in the 2 groups. Results: There was significantly less mediastinal chest tube drainage up to 48 h in the tranexamic acid group (432±210 mL) compared to the placebo group (649±235 mL, p=0.006). In the placebo group, 43 (58) patients were given allogeneic blood during hospital stay compared to 22 (25) in the tranexamic acid group (p<0.001). No significant difference in postoperative complications was seen. Conclusion: The use of low-dose tranexamic acid can significantly reduce blood loss and need for transfusion, with no increase in complications. © The Author(s) 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav

    Timoshenko beam model for buckling of piezoelectric nanowires with surface effects

    Get PDF
    This paper investigates the buckling behavior of piezoelectric nanowires under distributed transverse loading, within the framework of the Timoshenko beam theory, and in the presence of surface effects. Analytical relations are given for the critical force of axial buckling of nanowires by accounting for the effects of surface elasticity, residual surface tension, and transverse shear deformation. Through an example, it is shown that the critical electric potential of buckling depends on both the surface stresses and piezoelectricity. This study may be helpful in the characterization of the mechanical properties of nanowires and in the calibration of the nanowire-based force sensors

    Fatigue behaviour of load-bearing polymeric bone scaffolds: A review

    Get PDF
    Bone scaffolds play a crucial role in bone tissue engineering by providing mechanical support for the growth of new tissue while enduring static and fatigue loads. Although polymers possess favourable characteristics such as adjustable degradation rate, tissue-compatible stiffness, ease of fabrication, and low toxicity, their relatively low mechanical strength has limited their use in load-bearing applications. While numerous studies have focused on assessing the static strength of polymeric scaffolds, little research has been conducted on their fatigue properties. The current review presents a comprehensive study on the fatigue behaviour of polymeric bone scaffolds. The fatigue failure in polymeric scaffolds is discussed and the impact of material properties, topological features, loading conditions, and environmental factors are also examined. The present review also provides insight into the fatigue damage evolution within polymeric scaffolds, drawing comparisons to the behaviour observed in natural bone. Additionally, the effect of polymer microstructure, incorporating reinforcing materials, the introduction of topological features, and hydrodynamic/corrosive impact of body fluids in the fatigue life of scaffolds are discussed. Understanding these parameters is crucial for enhancing the fatigue resistance of polymeric scaffolds and holds promise for expanding their application in clinical settings as structural biomaterials. Statement of Significance: Polymers have promising advantages for bone tissue engineering, including adjustable degradation rates, compatibility with native bone stiffness, ease of fabrication, and low toxicity. However, their limited mechanical strength has hindered their use in load-bearing scaffolds for clinical applications. While prior studies have addressed static behaviour of polymeric scaffolds, a comprehensive review of their fatigue performance is lacking. This review explores this gap, addressing fatigue characteristics, failure mechanisms, and the influence of parameters like material properties, topological features, loading conditions, and environmental factors. It also examines microstructure, reinforcement materials, pore architectures, body fluids, and tissue ingrowth effects on fatigue behaviour. A significant emphasis is placed on understanding fatigue damage progression in polymeric scaffolds, comparing it to natural bone behaviour

    Wireless sensor network performance analysis and effect of blackhole and sinkhole attacks

    Get PDF
    The widespread usage of Wireless sensor networks in various fields and application make it vulnerable to variety of security threats and attacks. These security attacks occur when an adversary compromised a sensor node by inject false measurements and divert real time network traffic. Sinkhole and Blackhole attacks are very common attacks in network, where an attacker advertises un-authorized routing update in network. To deal with these types of attacks, there is a need to tighten the network security and prevent from attackers. In this study, we discuss security threats and presents the effects of Black and Sink hole attacks. Further, the study presents related work and current issues in wireless sensor network. The simulation results illustrated that, how these attacks affect the network performance

    Solvent-free synthesis of xanthene derivatives by Preyssler type heteropolyacid

    Get PDF
    Dimedone reacted with aromatic aldehydes and 3,4-methylenedioxyphenol or β-naphthol in the presence of a catalytic amount of Preyssler type heteropolyacid, H14[NaP5W30O110], as a green and reusable catalyst under solvent-free conditions to form a variety of  new xanthene derivatives in very good  yields.KEY WORDS: Xanthene derivatives, Solvent-free synthesis, Preyssler type heteropolyacid, 3,4-Methylene dioxyphenol, β-Naphthol, Three-component one-pot reactions Bull. Chem. Soc. Ethiop. 2011, 25(3), 399-406

    Study of type and frequency of Alfa-thalassemia mutations in a cohort of 3,823 patients from Isfahan Province, Iran

    Get PDF
    Introduction: Alpha-thalassemia (α-thalassemia) is caused by a range of mutations in the α-globin gene resulting in the complete reduction or absence of α-globin chain production. Material and methods: This study assessed the presence of α-thalassemia in 3,823 patients referred to Al-Zahra Hospital, Isfahan, Iran during a 10-year period (from 2012 to 2022). These patients experienced anaemia for more than ten years but had not the full indication for β-thalassemia or iron deficiency. Results: Based on the present assessment, 3,483 cases out of 3,823 suspicious cases had an α-Thalassemia-involved mutation (91.1%). According to the results, the most common detected mutation in the α-thalassemia carriers of Isfahan province was –α3.7 with a frequency of 81.58% (3,119 individuals), followed by α5nt (–TGAGG) (3.71% in total or 39.01% between 364 patients), polyadenylation signal mutations (polyA2) (14.28% between 364 patients), αcodon 19 (GCG4GC–, a2) (11.53%), –α3.7/–α3.7 (11.53%), –α20.5 (7.69%), Hb Constant Spring [Hb CS, a142, Stop →Gln; HBA2: c.427T4C] (5.7%), α4.2 (5.49) and – –MED (4.67%). Conclusion: The results of this investigation may be valuable for designing a program for carrier screening, premarital genetic counselling, and prenatal diagnosis in the Isfahan province
    corecore