New approaches to the diagnosis and management of microbial endophthalmitis

Endophthalmitis is a devastating ocular disease in which, despite adequate antibiotic cover, the final visual outcome for patients remains poor. In the search for other treatment modalities to aid in the management of these cases, the use of clarithromycin, as an anti-biofilm agent, was investigated. Results indicated that a greater number of culture negative cases demonstrated an improvement in vision of 6 Snellen lines when clarithromycin was used. In cases of presumed bacterial endophthalmitis, early diagnosis and appropriate treatment have been noted to be associated with a better visual outcome but currently, confirmation of the diagnosis of endophthalmitis (bacterial and / or fungal) is dependent on conventional techniques of microbiological isolation of organisms which require between 1-12 days. Furthermore, many samples prove to be culture negative. In this study, PCR technology has been successfully applied to the detection of bacteria and fungi in ocular samples from eyes with suspected endophthalmitis. Oligonucleotide primers based on the conserved sequences of the 16S rRNA gene (bacteria) and lanosterol 14 α-demethylase (Candida spp.), have been used to detect the presence of these pathogens. Restriction endonuclease digestion, DNA sequencing and cloning of the PCR product were used to enable species identification. Results demonstrated that PCR-based methods are able rapidly to confirm the presence of pathogens with high specificity and sensitivity. PCR based techniques have also been used to rule out with confidence the presence of pathogens, a unique advantage of this methodology. The use of molecular methods has significantly increased the number of intraocular samples from which a confirmed diagnosis is made and reduced the time to laboratory diagnosis. PCR based methods have demonstrated great potential in the rapid detection and identification of bacteria and Candida spp. in ocular samples and promise to provide a useful diagnostic tool for the future

Information Leakage Detection in Distributed Systems using Software Agents

Covert channel attacks utilize shared resources to indirectly transmit sensitive information to unauthorized parties. Current security mechanisms such as SELinux rely on tagging the filesystem with access control properties. However, such mechanisms do not provide strong protection against information laundering via covert channels. Colored Linux [20], an extension to SELinux, utilizes watermarking algorithms to “color” the contents of each file with their respective security classification to enhance resistance to information laundering attacks. In this paper, we propose a mobile agent-based approach to automate the process of detecting and coloring receptive hosts’ filesystems and monitoring the colored filesystem for instances of potential information leakage. Implementation details and execution results are included to illustrate the merits of the proposed approach

Designing a Framework for Target-Site Assignment in Naval Combat Management

In this study, using operational research techniques, a model has been presented to assess battlefield threat, to prioritise aggressive targets, to evaluate the capability of own sites and the risks of the conflict with the targets, to define conflict scenarios and finally to select the best scenario using an assignment model. The above proceedings were added as an intermediate phase of target-site assignment, called ‘deciding the best conflict scenario’, to the ‘threat assessment’ and ‘weapon-target assignment’ in the naval combat management system. For each of the own site, the data collected from the environment together with the panels of experts are shown in a two-dimensional matrix, in which the four areas of the matrix represent the conflict scenarios. Considering that the study was done in a simulated environment, the expert’s verification and the convergence of the results in Monte Carlo method were used to validate the research. The proposed model can offer optimised decision to the operational commander through predicting the battlefield and managing the site’s capacity and the interaction in between during the combat

Control-Flow Integrity for Real-Time Embedded Systems

Attacks on real-time embedded systems can endanger lives and critical infrastructure. Despite this, techniques for securing embedded systems software have not been widely studied. Many existing security techniques for general-purpose computers rely on assumptions that do not hold in the embedded case. This paper focuses on one such technique, control-flow integrity (CFI), that has been vetted as an effective countermeasure against control-flow hijacking attacks on general-purpose computing systems. Without the process isolation and fine-grained memory protections provided by a general-purpose computer with a rich operating system, CFI cannot provide any security guarantees. This work proposes RECFISH, a system for providing CFI guarantees on ARM Cortex-R devices running minimal real-time operating systems. We provide techniques for protecting runtime structures, isolating processes, and instrumenting compiled ARM binaries with CFI protection. We empirically evaluate RECFISH and its performance implications for real-time systems. Our results suggest RECFISH can be directly applied to binaries without compromising real-time performance; in a test of over six million realistic task systems running FreeRTOS, 85% were still schedulable after adding RECFISH

Perivascular macrophages in the neonatal macaque brain undergo massive necroptosis after simian immunodeficiency virus infection

We previously showed that rhesus macaques neonatally infected with simian immunodeficiency virus (SIV) do not develop SIV encephalitis (SIVE) and maintain low brain viral loads despite having similar plasma viral loads compared to SIV-infected adults. We hypothesize that differences in myeloid cell populations that are the known target of SIV and HIV in the brain contribute to the lack of neonatal susceptibility to lentivirus-induced encephalitis. Using immunohistochemistry and immunofluorescence microscopy, we examined the frontal cortices from uninfected and SIV-infected infant and adult macaques (n = 8/ea) as well as adults with SIVE (n = 4) to determine differences in myeloid cell populations. The number of CD206+ brain perivascular macrophages (PVMs) was significantly greater in uninfected infants than in uninfected adults and was markedly lower in SIV-infected infants while microglia numbers were unchanged across groups. CD206+ PVMs, which proliferate after infection in SIV infected adults, did not undergo proliferation in infants. While virtually all CD206+ cells in adults are also CD163+, infants have a distinct CD206 single-positive population in addition to the double-positive population commonly seen in adults. Notably, we found that more than 60% of these unique CD206+CD163− PVMs in SIV-infected infants were positive for cleaved caspase-3, an indicator of apoptosis, and that nearly 100% of this subset were concomitantly positive for the necroptosis marker receptor interacting protein kinase-3 (RIP3). These findings show that distinct subpopulations of PVMs found in infants undergo programmed cell death instead of proliferation following SIV infection, which may lead to the absence of PVM-dependent SIVE and the limited size of the virus reservoir in the infant brain. Includes Supplementary Material