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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

In vitro antimalarial efficacy enhancement of selected antibiotics with PheroidTM technology / E.C. van Niekerk

Van Niekerk, Elizabeth Catharina January 2010 (has links)
The Plasmodium falciparum parasite, carried by Anopheles mosquitoes, is currently a global problem due to the rising incidence of resistance of the parasite to available antimalaria drugs. Resistance and difficult treatment groups, including pregnant woman and young children, are pressing for the development of new, safe and effective prophylactic and treatment antimalarials. Because of the extensive process of developing new drugs, researchers and health care professionals have turned to combination therapy where a fast acting antimalarial is combined with slower acting drugs, such as antibiotics. The macrolide antibiotics, erytbromycin and azithromycin, have been studied to a limited extent for their potential antimalarial effect. Certain advantages, such as their safety profile (especially that of azithromycin) in pregnancy and administration to young children, motivates continual research into the advancement of the effect these drugs exude on malaria. Drug delivery systems contribute to the efficacy of medicines, conquering several difficulties of treatment with oral medication. Pheroid™ technology is a patented drug delivery system, mainly consisting of plant and essential fatty acids, and has been demonstrated to entrap, carry and deliver pharmacologically active compounds and other useful molecules. This study compared the in vitro effects of the macrolide antibiotics on the growth of a chloroquine-resistant strain (RSA 11) of Plasmodium falciparum to the effects of the macrolides entrapped in Pheroid™ vesicles on the same strain over and extended observation period of 144 hours. ELISA assays were conducted by analysing the HRP II (histidine-rich protein) levels on a pre-coated microtitre plate. The effects of the type of formulation, concentration and time were compared. The in vitro difference between erythromycin alone and entrapped in Pheroid™ vesicles were found to be statistically significant (p = 0.000000) while the effects of both formulations did not seem to be concentration dependant (p = 0.628424). Prolonged exposure was also statistically meaningful (p = 0.008268), though it seems that exposure need not exceed 96 hours. The type of formulation, in the case of azithromycin (azithromycin alone vs. azitbromycin entrapped in Pheroid™ vesicles), proved statistically significant (P = 0.002572), while neither formulation seemed concentration dependant (P = 0.427731). Prolonged exposure was found to be statistically insignificant for azithromycin (P = 0.221941). / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2010.
92

In vitro antimalarial efficacy enhancement of selected antibiotics with PheroidTM technology / E.C. van Niekerk

Van Niekerk, Elizabeth Catharina January 2010 (has links)
The Plasmodium falciparum parasite, carried by Anopheles mosquitoes, is currently a global problem due to the rising incidence of resistance of the parasite to available antimalaria drugs. Resistance and difficult treatment groups, including pregnant woman and young children, are pressing for the development of new, safe and effective prophylactic and treatment antimalarials. Because of the extensive process of developing new drugs, researchers and health care professionals have turned to combination therapy where a fast acting antimalarial is combined with slower acting drugs, such as antibiotics. The macrolide antibiotics, erytbromycin and azithromycin, have been studied to a limited extent for their potential antimalarial effect. Certain advantages, such as their safety profile (especially that of azithromycin) in pregnancy and administration to young children, motivates continual research into the advancement of the effect these drugs exude on malaria. Drug delivery systems contribute to the efficacy of medicines, conquering several difficulties of treatment with oral medication. Pheroid™ technology is a patented drug delivery system, mainly consisting of plant and essential fatty acids, and has been demonstrated to entrap, carry and deliver pharmacologically active compounds and other useful molecules. This study compared the in vitro effects of the macrolide antibiotics on the growth of a chloroquine-resistant strain (RSA 11) of Plasmodium falciparum to the effects of the macrolides entrapped in Pheroid™ vesicles on the same strain over and extended observation period of 144 hours. ELISA assays were conducted by analysing the HRP II (histidine-rich protein) levels on a pre-coated microtitre plate. The effects of the type of formulation, concentration and time were compared. The in vitro difference between erythromycin alone and entrapped in Pheroid™ vesicles were found to be statistically significant (p = 0.000000) while the effects of both formulations did not seem to be concentration dependant (p = 0.628424). Prolonged exposure was also statistically meaningful (p = 0.008268), though it seems that exposure need not exceed 96 hours. The type of formulation, in the case of azithromycin (azithromycin alone vs. azitbromycin entrapped in Pheroid™ vesicles), proved statistically significant (P = 0.002572), while neither formulation seemed concentration dependant (P = 0.427731). Prolonged exposure was found to be statistically insignificant for azithromycin (P = 0.221941). / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2010.
93

Untersuchung der Gruppen GL(s, Zn) und SL(s, Zn) zur Nutzung in der Kryptographie

Baumgart, Matthias. Unknown Date (has links)
Universiẗat, Diss., 2005--Giessen.
94

Hardware Root of Trust for Linux Based Edge Gateway

Al-Galby, Mohamed, Arezou, Madani January 2018 (has links)
Linux-based Edge Gateways that connects hundreds or maybe thousands of IoT devices, are exposed to various threats and cyber-attacks from the internet. These attacks form a considerable risk targeting the privacy and confidentiality of IoT devices throughout their gateways. Many researches and studies have been conducted to alleviate such a problem. One of the solutions can be achieved by building a root of trust based on a hardware module such as Trusted Platform Module (TPM) or software like Trusted Execution Environment (TEE). In this work, we provide a solution to the problem by enabling Hardware Root of Trust (HRoT) using TPM on a product from HMS Industrial Network AB known as GWen board, a Linux-based embedded system, used as gateway to connect IoT devices. We describe a method that uses the processor of the GWen (i.e. Zynq-7020 FPGA SoC) to enable secure boot. Besides, we provide a method to enable the TPM chip mounted on the GWen (i.e. SLB 9670 TPM 2.0) using TPM Software Stack TSS 2.0. We demonstrated, in detail, various use-cases using the TPM on GWen including cryptographic keys generation, secure key storage and key usage for different cryptographic operations. Furthermore, we conducted an analysis to the adopted solution by inspecting the latency of TPM commands on the GWen gateway. According to the high restrictions of TPM 2.0 specifications and based on our results, adding the TPM 2.0 to the IoT gateway GWen will enhance the security of its Linux distribution and will makes it possible to securely identify and authenticate the gateway on the network based on its secret keys that are stored securely inside its TPM.
95

Parasympathetic Nervous System Function, Temperament, and Adjustment in Preschoolers

January 2012 (has links)
abstract: This study examines the relations among three aspects of temperament (shyness, impulsivity, and effortful control), resting respiratory sinus arrhythmia (RSA) recorded during a calming film and RSA suppression during three behavioral measures of effortful control, and adjustment (anxiety and externalizing behavior) in a sample of 101 preschool-age children. Principal components analysis was used to create composites for effortful control, shyness, impulsivity, anxiety, and externalizing behavior, and hierarchical regression analysis was used to test the study hypotheses. As expected, baseline RSA was negatively related to effortful control in shy children, but was unrelated to effortful control in children who were not shy. It was hypothesized that high baseline RSA would reduce the relation between shyness and anxiety, and between impulsivity and externalizing behavior; this hypothesis was supported for externalizing behavior, but not for anxiety. The interaction between impulsivity and RSA as a predictor of externalizing was statistically independent of effortful control, indicating that these are unique effects. Finally, it was hypothesized that RSA suppression would be positively related to effortful control for children low, but not high, in shyness. There was a marginal interaction between shyness and RSA suppression, with RSA suppression marginally negatively related to EC for children low in shyness, but unrelated to effortful control for children high in shyness; the direction of this association was opposite predictions. These findings indicate that RSA is more strongly related to effortful control for children high in shyness, and that it consequently may not be appropriate to use RSA as an index of EC for all children. This study also draws attention to the need to consider the context in which baseline RSA is measured because a true baseline may not be obtained for shy children if RSA is measured in an unfamiliar laboratory context. The finding that high RSA moderated (but did not eliminate) the relation between impulsivity and externalizing behavior is consistent with the conceptualization of RSA as a measure of self-regulation, but further research is needed to clarify the mechanism underlying this effect. / Dissertation/Thesis / M.A. Psychology 2012
96

Comparison of security level and current consumption of security implementations for MQTT

Carlsson, Fredrik, Eriksson, Klas-Göran January 2018 (has links)
IoT is a rapidly growing area with products in the consumer, commercial and industrial market. Collecting data with multiple small and often battery-powered devices sets new challenges for both security and communication. There has been a distinct lack of a IoT specific communication protocols. The industry has had to use bulky interfaces not suitable for resource-constrained devices. MQTT is a standardised communication protocol made for the IoT industry. MQTT does however not have built-in security and it is up to the developers to implement a suitable security countermeasure. To evaluate how different security countermeasures impact MQTT in complexity, current consumption and security the following research questions are answered. How do you derive a measurement from the SEF that can be compared with a current consumption measurement? Which level of security, according to the SEF, will RSA, AES and TLS provide to MQTT when publishing a message to a broker? What level of complexity is added to MQTT when using chosen security countermeasure? Which of the analysed security countermeasure upholds an adequate security level while also having a low current consumption? To answer the above research questions an experiment approach has been used. Implementations of TLS, RSA and AES have been evaluated to measure how they affect the security level and current consumption of an MQTT publication, compared to no security countermeasures at all.Both RSA and AES had the same security level, but the current consumption for RSA was four times higher. The experiment showed that the security level is significantly higher for TLS, while it also has the highest current consumption. The security countermeasure evaluated differs greatly. TLS provides complete protections, while RSA and AES lacks authentication and does not ensure integrity and non-repudiation.Even if the current consumption for TLS is higher, the security it provides make it unreasonable to recommend any of the other security countermeasure implementations.
97

Predicting the Developmental Trajectories of Externalizing and Internalizing Behaviors from Parenting Quality and Children's Respiratory Sinus Arrhythmia

January 2014 (has links)
abstract: The current study delineated the developmental trajectories of early childhood externalizing and internalizing symptoms reported by mothers and fathers, and examined the role of the 18-month observed parenting quality × Respiratory Sinus Arrhythmia (RSA) interaction in predicting these trajectories. Child sex was tested as a covariate and moderator. It was found that children's low baseline RSA or high RSA reactivity , in comparison to high baseline RSA or low RSA reactivity , was more reactive as a function of early parenting quality when predicting the development of early childhood problem symptoms. Differential patterns of the interaction between parenting quality and RSA were detected for mothers' and fathers' reports. Mother-reported models showed a diathesis-stress pattern, whereas the father-reported model showed a vantage-sensitivity pattern, especially for internalizing symptoms. This may imply the potential benefit of fathers' active engagement in children's early development. In addition, the effect of the parenting quality × RSA interaction in predicting the mother-reported models was found to be further moderated by child sex. Specifically, the parenting quality × baseline RSA interaction was significantly predictive of girls' 54-month internalizing, and the parenting quality × RSA reactivity interaction significantly predicted boys' internalizing slope. Girls with low baseline RSA or boys with high RSA reactivity were vulnerable to the less positive parenting, exhibiting high levels of 54-month internalizing symptoms or slow decline in internalizing over time, respectively. Future research directions were discussed in terms of integrating the measures of SNS and PNS in psychopathology study, exploring the mechanisms underlying the sex difference in parenting quality × RSA interaction, and comparing the findings of children's typical and atypical development. / Dissertation/Thesis / Masters Thesis Psychology 2014
98

Alguns métodos de criptografia

Silva, Josemberg dos Santos 26 August 2016 (has links)
Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-10-04T12:51:12Z No. of bitstreams: 1 PDF - Josemberg dos Santos Silva.pdf: 1121305 bytes, checksum: 92540058586a498be93dd4935979151b (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-10-17T13:32:29Z (GMT) No. of bitstreams: 1 PDF - Josemberg dos Santos Silva.pdf: 1121305 bytes, checksum: 92540058586a498be93dd4935979151b (MD5) / Made available in DSpace on 2016-10-17T13:32:47Z (GMT). No. of bitstreams: 1 PDF - Josemberg dos Santos Silva.pdf: 1121305 bytes, checksum: 92540058586a498be93dd4935979151b (MD5) Previous issue date: 2016-08-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Within the context of designing a digital communication scheme, it is necessary to establish procedures to safeguard the confidentiality of data sent by electronic messages. In this sense, Coding Theory plays a central role. Since its development over the years, it has enabled the advancement of new electronic communication techniques with greater security. In particular, Cryptography that employs elements of Coding Theory has been increasingly employed and used every time a digital message is transmitted, in such a way that only the sender and the legitimate recipient may know its contents. It is within this process that we contemplate some concepts of Elementary Number Theory, which are the basis for the mathematical foundation necessary for the development of elements of Cryptography. Consequently, in this paper, we present some necessary results of the Number Theory to present some cryptographic methods. / Dentro do contexto de projetar esquema de comunicação digital, é necessário estabelecer um procedimento que permita o sigilo dos dados enviados por meio de mensagens eletrônicas. Nesta direção, a Teoria dos Códigos desempenha um papel central, pois seu desenvolvimento ao longo dos anos possibilitou o avanço de novas técnicas de comunicação eletrônica com maior segurança. Em particular, a Criptografia, que emprega elementos da Teoria dos Códigos, tem sido empregada cada vez mais e usada todas as vezes que se deseja transmitir uma mensagem digital, na qual apenas o remetente é o legítimo destinatário possam conhecer seu conteúdo. E neste processo que consideramos alguns conceitos da Teoria Elementar dos Números, que são base para a fundamentação matemática necessária para o desenvolvimento de elementos da Criptografia. A partir disso, apresentamos neste trabalho alguns resultados necessários da Teoria dos Números de modo a apresentar alguns métodos criptográficos.
99

Utvärdering av produkter för säker autentisering i Windowsmiljö / Evaluation of secure authentication products in a Windows environment

Backman, Mattias January 2004 (has links)
In this report hardware based alternatives to password authentication in a Windows domain are evaluated for the needs of a certain company. In order to investigate the demands on such alternatives interviews with people concerned have been carried out. The demands which resulted from the interviews have been used to select types of hardware tokens for evaluation. Two products which offer authentication with smart cards and USB tokens have been selected and closer evaluated. These are RSA Passage which offers both hardware options and Rainbow iKey which uses USB tokens. Both products are evaluated based on the demands and additional evaluation criteria. The information from the evaluations is used to compare the products.
100

Upgrading the SSL protocol to TLS in the Roxen WebServer

Svensson, Pär January 2002 (has links)
The company Roxen Internet Software have an implementation of the secure network protocol SSL (Secure Sockets Layer) which is used in their web server product. This report describes the upgrading of that implementation to the TLS1.0 (Transport Layer Security) standard. It also describes a performance investigation of the SSL/TLS support in the Roxen WebServer and compares it with other common web servers. The initial setup time for the secure SSL/TLS connection was found to be very long in the Roxen Webserver compared to its competitors. The main bottleneck, in the Roxen implementation, was found to be the modular exponentiation that is the core of the RSA decryption algorithm. One suggested improvement is to upgrade the bignumber numerical package used in Roxen WebServer, GMP (The GNU Multiple Precision arithmetic library) from version 2.0 to version 4.0. The newer version of the bignumber package have been measured to have considerably better performance in its modular exponentation operation.

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