Effect of fibre treatments on mechanical properties of flax/tannin composites

Due to the inherent environmental benefits of using natural resin (tannin) and natural fibre (flax), flax/tannin composites could be potentially used for vehicle applications. One of the main limitations is the hydrophilic property of flax, resulting in the poor fibre/hydrophobic matrix interface quality. Alkali, acetylation, silane treatment and enzymatic treatment were selected to modify non-woven flax mats to prepare the composites. The fibre morphology was studied through scanning electronic microscopes (SEM). The effects of fibre pre-treatments on dynamic and static mechanical properties of composites were investigated through adequate experiments, such as dynamic mechanical analysis (DMA) and static tensile testing. The modified rougher fibre surface broadened the glass transition peaks of composites due to the improved surface adhesion. However, there is no big improvement of tensile strength after modifications. The pure NaOH (sodium hydroxide) treated composites remain the tensile properties and offer good flax/tannin wettability

A MASS SPECTROMETRY-BASED STUDY OF SERUM BUTYRYLCHOLINESTERASE INHIBITION FROM PESTICIDE EXPOSURE AND ORGANOPHOSPHATE PESTICIDE-INDUCED PROTEOME ALTERATION

Pesticides including organophosphates (OPs) and carbamates (CBs) are widelyused to control undesirable pests. These compounds are neurotoxic and inhibithydrolysis of the neurotransmitter acetylcholine by acetylcholinesterase. Public healthconcerns have increased with the escalating usage of pesticides. Reliable monitoringprograms are required to detect and quantify pesticide exposure, as well as to promotean understanding of their neurotoxic properties. In this dissertation, both theanticholinergic (Part I) toxicity and neurotoxicity in neuroblastoma cells (Part II) ofpesticides were explored using mass spectrometry (MS). The high sensitivity andhigh-throughput of this technique renders it well-suited for proteomics analysis.Part I describes the study of butyrylcholinesterase (BChE) inhibition resultingfrom OP and CB exposure. The main hypothesis of Part I is that the specialmodification of BChE can provide the origin and extent of pesticide exposure. A novelmethod for detection and quantification of pesticide exposure was designed using aproteomics approach and equine BChE (eBChE) as a model system. The methodologyfeatured detection and analysis of phosphorylated or carbamylated peptides at theactive site serine residue. The developed technique was successfully applied towardsthe study of human BChE (hBChE) inhibition in vitro and in serum samples. Aspecially designed affinity column enabled an isolation of BChE from serum. EnrichedBChE was subjected to enzymatic digestion by a novel on-bead double digestionprotocol. LC/MS/MS was employed to produce a calibration system for the analysis ofhBChE inhibition, which was then applied towards quantification of the enzyme.Part II describes a proteomic study of the neurotoxicity in neuroblastoma cellscaused from chlorpyrifos (CPF), an organophosphate pesticide. The concerns of CPFexposure to pregnant women, infants and children are increasing due todevelopmentally neurotoxic effects of this chemical. The main hypothesis of Part II isthat CPF can cause protein alterations and these altered proteins can be detected usingproteomics. Systematic studies at subcellular levels evaluated proteome changes inSH-SY5Y cells exposed to CPF. Two-dimensional gel electrophoresis (2DE) wasapplied with MALDI-TOF-MS to analyze differential protein expression. Thirty sevencommon unique altered proteins were identified, which play important roles inmetabolic pathway

Endpoints and Interdependencies in Internet of Things Residual Artifacts: Measurements, Analyses, and Insights into Defenses

The usage of Internet of Things (IoT) devices is growing fast. Moreover, the lack of security measures among the IoT devices and their persistent online connection give adversaries an opportunity to exploit them for multiple types of attacks, such as distributed denial-of-service (DDoS). To understand the risks of IoT devices, we analyze IoT malware from an endpoint standpoint. We investigate the relationship between endpoints infected and attacked by IoT malware, and gain insights into the underlying dynamics in the malware ecosystem. We observe the affinities and different patterns among endpoints. Towards this, we reverse-engineer 2,423 IoT malware samples and extract IP addresses from them. We further gather information about these endpoints from Internet-wide scans. For masked IP addresses, we examine their network distribution, with networks accumulating more than 100 million endpoints. Moreover, we conduct a network penetration analysis, leveraging information such as active ports, vulnerabilities, and organizations. We discover the possibility of ports being an entry point of attack and observe the low presence of vulnerable services in dropzones. Our analysis shows the tolerance of organizations towards endpoints with malicious intent. To understand the dependencies among malware, we highlight dropzone characteristics including spatial, network, and organizational affinities. Towards the analysis of dropzones\u27 interdependencies and dynamics, we identify dropzones chains. In particular, we identify 56 unique chains, which unveil coordination among different malware families. Our further analysis of chains suggests a centrality-based defense and monitoring mechanism to limit malware propagation. Finally, we propose a defense based on the observed measures, such as the blocked/blacklisted IP addresses or ports. In particular, we investigate network-level and country-level defenses, by blocking a list of ports that are not commonly used by benign applications, and study the underlying issues and possible solutions of such a defense

WS-Pro: a Petri net based performance-driven service composition framework

As an emerging area gaining prevalence in the industry, Web Services was established to satisfy the needs for better flexibility and higher reliability in web applications. However, due to the lack of reliable frameworks and difficulties in constructing versatile service composition platform, web developers encountered major obstacles in large-scale deployment of web services. Meanwhile, performance has been one of the major concerns and a largely unexplored area in Web Services research. There is high demand for researchers to conceive and develop feasible solutions to design, monitor, and deploy web service systems that can adapt to failures, especially performance failures. Though many techniques have been proposed to solve this problem, none of them offers a comprehensive solution to overcome the difficulties that challenge practitioners. Central to the performance-engineering studies, performance analysis and performance adaptation are of paramount importance to the success of a software project. The industry learned through many hard lessons the significance of well-founded and well-executed performance engineering plans. An important fact is that it is too expensive to tackle performance evaluation, mostly through performance testing, after the software is developed. This is especially true in recent decades when software complexity has risen sharply. After the system is deployed, performance adaptation is essential to maintaining and improving software system reliability. Performance adaptation provides techniques to mitigate the consequence of performance failures and therefore is an important research issue. Performance adaptation is particularly meaningful for mission-critical software systems and software systems with inevitable frequent performance failures, such as Web Services. This dissertation focuses on Web Services framework and proposes a performance-driven service composition scheme, called WS-Pro, to support both performance analysis and performance adaptation. A formalism of transformation from WS-BPEL to Petri net is first defined to enable the analysis of system properties and facilitate quality prediction. A state-transition based proof is presented to show that the transformed Petri net model correctly simulates the behavior of the WS-BPEL process. The generated Petri net model was augmented using performance data supplied by both historical data and runtime data. Results of executing the Petri nets suggest that optimal composition plans can be achieved based on the proposed method. The performance of service composition procedure is an important research issue which has not been sufficiently treated by researchers. However, such an issue is critical for dynamic service composition, where re-planning must be done in a timely manner. In order to improve the performance of service composition procedure and enhance performance adaptation, this dissertation presents an algorithm to remove loops in the reachability graphs so that a large portion of the computation time of service composition can be moved to a pre-processing unit; hence the response time is shortened during runtime. We also extended the WS-Pro to the ubiquitous computing area to improve fault-tolerance