Performance of free space optical communication using M-array receivers at atmospheric conditions

Abstract: In free space optical (FSO) communication links, atmospheric parameters including absorption, scattering and turbulence have significant impacts on the quality of laser beams propagating through the atmosphere. Absorption and/or scattering, due to atmospheric particles result in optical losses, whereas turbulence contributes to the intensity scintillation that can severely impair the operation of FSO communications systems. In this paper, using a modified model we analyze the atmospheric effects on the signal-to-noise ratio (SNR) and the bit error rate (BER) of an FSO system. We show that there is an improvement in BER when using M-array receivers instead of one a single receiver

Functional Polymers with Defined Architecture for Biointerface Interactions: From Nanoparticles to Nanosheets

This work focused on the development of new functional polymers with defined architectures for biointerface interactions. The first project was a comparative study of a 2D polymer and its 3D counterpart. To this end, a bottom-up approach using graphene as a 2D template was developed to synthesize two-dimensional hyperbranched polyglycerol (2D-hPG). A layer of hPG bearing azide functional groups was attached to a graphene template using acid-sensitive linkers. Next, using tripropargylamine loaded on the surface of graphene, lateral cross-linking of the polyglycerol units was performed. Following this, the nanosheets were detached and then separated from the graphene through acidification and centrifugation, respectively. Afterward, nanosheets were sulfated to yield heparin mimicking sulfate proteoglycan (2DhPGS). Aiming to examine the relevance of two-dimensionality in bio-nano interactions, 3D equivalents of the nanosheets with similar average sizes and surface charges were synthesized. The results of this study showed that 2D-hPGS was able to act as an extracellular matrix mimic and inhibit the replication of enveloped viruses, such as HSV-1 and SARS-CoV-2. The inhibitory effect of 2D-hPGS is approximately four times better than that of its 3D analogs (3D-hPGS). The superiority of the 2D inhibitor over its 3D spherical counterpart can be attributed to the high aspect ratio of the 2D-hPGS. Based on our findings from the first project on the nano-bio interactions of synthesized extracellular matrix mimics, a second project to develop alternative polymeric architectures that can be synthesized and scaled up with ease was designed. In addition, the project aimed to develop an antiviral compound with virucidal properties. Therefore, the compounds were designed in a synergistic manner by using alkyl chains for hydrophobic interactions and sulfate moieties for electrostatic interactions. The development of highly sulfated hPG containing sulfated alkyl chains was obtained using a one-pot reaction. Increasing the length of the alkyl chains resulted in higher hydrophobicity and thus virucidal activity was achieved. Against HSV-1, compounds with short (C3) and medium (C6) alkyl chains demonstrated strong antiviral activity with IC50 values in the nanomolar range yet provided only virustatic properties. In contrast, the one with long alkyl chains (C9) exhibited irreversible virucidal properties. The first two projects focused on the development of polymers with diverse architectures to be used in nano-bio interactions in vitro. In the third project, block-co-polymer architectures were developed aimed at an ex vivo skin penetration and dermal drug delivery study. Toward this end, a series of anionic amphiphilic block-co-polypeptides with different hydrophobic to hydrophilic ratios have been synthesized using NCA and condensation-activated monomer polymerization. The nanocarriers were loaded with m-THPP. According to the results, the loading capacity of the block-co-polypeptides with moderate hydrophobic content was found to be maximum (4 wt.%). The nanocarriers also self-assembled into approximately 200 nm solid nanoparticles in an aqueous solution and improved the release of m-THPP in an acidic environment (pH 5.5-6.5) at a temperature of 32 °C, which is similar to that found on the skin surface.Ziel dieser Arbeit war die Entwicklung neuer funktioneller Polymere mit kontrollierten Architekturen für die Interaktion mit Bioschnittstellen. Das erste Projekt war eine vergleichende Studie eines 2D-Polymers und seines 3D-Gegenstücks. Zu diesem Zweck wurde ein Bottom-up-Ansatz mit Graphen als 2D-Vorlage entwickelt, um zweidimensionales hyperverzweigtes Polyglycerin (2D-hPG) zu synthetisieren. Eine Schicht aus hPG, die funktionelle Azidgruppen trägt, wurde mit Hilfe säureempfindlicher Linker an eine Graphenvorlage gebunden. Anschließend wurden die Polyglycerin-Einheiten mit Hilfe von Tripropargylamin auf der Graphenoberfläche lateral vernetzt. Anschließend wurden die Nanoblätter abgelöst und durch Ansäuern bzw. Zentrifugieren vom Graphen getrennt. Um Heparinsulfat-Proteoglykane zu imitieren, wurde 2D-hPG sulfatiert, was zu 2D-hPGS führte. Um die Rolle der Zweidimensionalität bei Bio-Nano-Wechselwirkungen zu untersuchen, wurden 3D-Analoga der Nanosheets mit ähnlichen Durchschnittsgrößen und Oberflächenladungen synthetisiert. Die Ergebnisse dieser Studie zeigt, dass 2D-hPGS in der Lage war, als extrazelluläre Matrixnachahmung zu fungieren und die Replikation von behüllten Viren wie HSV-1 und SARS-CoV-2 zu hemmen. Die hemmende Wirkung von 2DhPGS ist etwa viermal besser als die seiner 3D-Analoga (3D-hPGS). Die Überlegenheit des 2D-Hemmstoffs gegenüber seinem sphärischen 3D-Gegenstück kann auf das hohe Seitenverhältnis des 2D-hPGS zurückgeführt werden. Auf der Grundlage unserer Erkenntnisse aus dem ersten Projekt über die Nano-Bio-Wechselwirkungen von synthetisierten extrazellulären Matrixnachbildungen wurde ein zweites Projekt zur Entwicklung alternativer Polymerarchitekturen konzipiert, die sich leicht synthetisieren und in größerem Maßstab herstellen lassen. Darüber hinaus zielte das Projekt auf die Entwicklung einer antiviralen Verbindung mit viruziden Eigenschaften ab. Daher wurden die Verbindungen auf synergistische Weise entwickelt, indem Alkylketten für hydrophobe Wechselwirkungen und Sulfateinheiten für elektrostatische Wechselwirkungen verwendet wurden. Die Entwicklung von hoch sulfatiertem hPG, das sulfatierte Alkylketten enthält, wurde durch eine Eintopfreaktion erreicht. Mit zunehmender Länge der Alkylketten wurde eine höhere Hydrophobie und damit eine viruzide Aktivität erzielt. Gegen HSV-1 zeigten die Verbindungen mit kurzen (C3) und mittleren (C6) Alkylketten eine starke antivirale Aktivität mit IC50-Werten im nanomolaren Bereich, aber nur virustatische Eigenschaften. Die Verbindung mit langen Alkylketten (C9) hingegen wies irreversible viruzide Eigenschaften auf. Die ersten beiden Projekte konzentrierten sich auf die Entwicklung von Polymeren mit unterschiedlichen Architekturen, die für Nano-Bio-Interaktionen in vitro verwendet werden sollen. Im dritten Projekt werden Block-Co-Polymer-Architekturen für eine Studie zur ex vivo Hautpenetration und dermalen Wirkstoffabgabe entwickelt. Zu diesem Zweck wurde eine Reihe von anionischen amphiphilen Block-Co-Polypeptiden mit unterschiedlichen hydrophoben zu hydrophilen Verhältnissen mittels NCA und kondensationsaktivierter Monomer polymerisation synthetisiert. Die Nanocarrier wurden mit m-THPP beladen. Die Ergebnisse zeigen, dass die Beladungskapazität der Block-Co-Polypeptide mit moderatem hydrophobem Anteil am höchsten ist (4 Gew.-%). Die Nanoträger formten in einer wässrigen Lösung feste Nanopartikeln mit einer Größe von ca. 200 nm und verbesserten die Freisetzung von m-THPP in einer sauren Umgebung (pH-Wert 5,5-6,5) bei einer Temperatur von 32 °C, die derjenigen auf der Hautoberfläche ähnlich ist

Classification of Epileptic EEG Signals by Wavelet based CFC

Electroencephalogram, an influential equipment for analyzing humans activities and recognition of seizure attacks can play a crucial role in designing accurate systems which can distinguish ictal seizures from regular brain alertness, since it is the first step towards accomplishing a high accuracy computer aided diagnosis system (CAD). In this article a novel approach for classification of ictal signals with wavelet based cross frequency coupling (CFC) is suggested. After extracting features by wavelet based CFC, optimal features have been selected by t-test and quadratic discriminant analysis (QDA) have completed the Classification.Comment: Electroencephalogram; Wavelet Decomposition; Cross Frequency Coupling;Quadratic Discriminant Analysis; T-test Feature Selectio

Considering supply risk for supplier selection using an integrated framework of data envelopment analysis and neural networks

For many years, supplier selection as an important multi-criteria decision has attracted both the researchers and practitioners. Recently, high incidences of natural disasters, terrorism attacks, labor strikes, and other kinds of risks, also known as disruptions, indicate the vulnerability of procurement process to these unpredicted events. In this study, a new framework is introduced to select suppliers while considering the supply risks. In the proposed framework, an expert is asked to determine the reliability of each procurement element (i.e., production, transportation, and communication) based on some proposed risk factors. Then, a distinct Multi-Layer Perceptron (MLP) network is trained to play the role of the expert opinion for estimating the reliability scores of each procurement. In addition to reliabilities, the Data Envelopment Analysis (DEA) is used to take into account the conventional selection criteria: price, delivery, quality, and capacity. A set of Pareto-optimal suppliers is obtained from the combination of efficiencies and reliability scores. Finally, the decision maker is recommended to choose between the non-dominated suppliers. Obtained experiment results indicate the effectiveness of the proposed framework

Examining the simple and multiple relationship of parenting styles and early life trauma with narcissistic personality in university students

According to the high prevalence of narcissistic personality among normal populations, this study was conducted to found out the simple and multiple relationships of parenting styles and early traumas with narcissism personality in university students. The statistical society of current research included all students of Shahid Chamran University of Ahwaz. To perform this research, 314 students (159 female, 155 male) were selected by multistage randomly sampling method and complete narcissism personality inventory 16 items (Ames et al, 2006), parenting styles ( bum rind, 1990) and early trauma inventory. The data of questionnaire were analyzed by multiple regressions in stepwise and entry methods .The results of multiple regression analysis indicated that 66 percent narcissism personality variance in students was explained by parenting styles and traumas in early life. Also, early life trauma, avoidant and secure attachment emerged as the strongest predictors of narcissism personality in students. Given the role of parenting styles and early life trauma on the making of narcissistic personality in students, recommended that a set of training program will be used by specialist to prevent the narcissistic personality tendency.