Process of designing robust, dependable, safe and secure software for medical devices: Point of care testing device as a case study

This article has been made available through the Brunel Open Access Publishing Fund.Copyright © 2013 Sivanesan Tulasidas et al. This paper presents a holistic methodology for the design of medical device software, which encompasses of a new way of eliciting requirements, system design process, security design guideline, cloud architecture design, combinatorial testing process and agile project management. The paper uses point of care diagnostics as a case study where the software and hardware must be robust, reliable to provide accurate diagnosis of diseases. As software and software intensive systems are becoming increasingly complex, the impact of failures can lead to significant property damage, or damage to the environment. Within the medical diagnostic device software domain such failures can result in misdiagnosis leading to clinical complications and in some cases death. Software faults can arise due to the interaction among the software, the hardware, third party software and the operating environment. Unanticipated environmental changes and latent coding errors lead to operation faults despite of the fact that usually a significant effort has been expended in the design, verification and validation of the software system. It is becoming increasingly more apparent that one needs to adopt different approaches, which will guarantee that a complex software system meets all safety, security, and reliability requirements, in addition to complying with standards such as IEC 62304. There are many initiatives taken to develop safety and security critical systems, at different development phases and in different contexts, ranging from infrastructure design to device design. Different approaches are implemented to design error free software for safety critical systems. By adopting the strategies and processes presented in this paper one can overcome the challenges in developing error free software for medical devices (or safety critical systems).Brunel Open Access Publishing Fund

Security Framework for Managing Data Security within Point of Care Tests

Point of Care (PoC) devices and systems can be categorized into three broad classes (CAT 1, CAT 2, and CAT 3) based on the context of operation and usage. In this paper, the categories are defined to address certain usage models of the PoC device. PoC devices that are used for PoC testing and diagnostic applications are defined CAT 1 devices; PoC devices that are used for patient monitoring are defined as CAT 2 devices (PoCM); PoC devices that are used for as interfacing with other devices are defined as CAT 3 devices (PoCI). The PoCI devices provide an interface gateway for collecting and aggregating data from other medical devices. In all categories, data security is an important aspect. This paper presents a security framework concept, which is applicable for all of the classes of PoC operation. It outlines the concepts and security framework for preventing security challenges in unauthorized access to data, unintended data flow, and data tampering during communication between system entities, the user, and the PoC system. The security framework includes secure layering of basic PoC system architecture, protection of PoC devices in the context of application and network. Developing the security framework is taken into account of a thread model of the PoC system. A proposal for a low-level protocol is discussed. This protocol is independent of communications technologies, and it is elaborated in relation to providing security. An algorithm that can be used to overcome the threat challenges has been shown using the elements in the protocol. The paper further discusses the vulnerability scanning process for the PoC system interconnected network. The paper also presents a four-step process of authentication and authorization framework for providing the security for the PoC system. Finally, the paper concludes with the machine to machine (M2M) security viewpoint and discusses the key stakeholders within an actual deployment of the PoC system and its security challenges

A study on biofilm production and antifungal drug resistance among Candida species from vulvovaginal and bloodstream infections

Sanyuktha Tulasidas,1 Pooja Rao,2 Sevitha Bhat,2 Radhakrishna Manipura1 1Department of Microbiology, Kasturba Medical College, Manipal Academy of Higher Education, Mangalore, Manipal, India; 2Department of Microbiology, Kasturba Medical College, Manipal Academy of Higher Education, Manipal McGill Center for Infectious Diseases, Mangalore, Manipal, India Introduction: Candida species, one among the opportunistic fungi, has become a common pathogen causing vaginal thrush and nosocomial bloodstream infections (BSIs). This study aims to evaluate the prevalence and antifungal susceptibility of various Candida species and slime production by Candida species in BSIs and vulvovaginal candidiasis (VVC). Materials and methods: A total of 176 samples were collected for a period of 1 year. Antifungal susceptibility testing and biofilm production testing were performed by the Kirby-Bauer method and crystal violet assay, respectively. Results: Out of 176 samples, 74 (42%) were from BSIs and 102 (58%) were from VVC. The biofilm production was comparatively high in blood isolates, 55 (74%), than cervical isolates, 45 (44%). Increase in the trends of non-albicans Candida (NAC) species was seen in our setup. Good susceptibility rates were seen among Candida species, 82.38% to voriconazole and an increasing resistance pattern of 26.13% to fluconazole. Conclusion: Speciation of Candida becomes important as the prevalence of NAC is increasing. Antifungal susceptibility testing by the disk diffusion method is cost effective and should be adopted in routine testing as there is an increasing azole resistance, especially in invasive NAC infections. In this study, there was no correlation of antifungal drugs with the biofilm production. Keywords: biofilm, Candida, azoles, vulvovaginal, bloodstream infection

The Effect of Mg2+, Cu2+ and Zn2+ pre-treatment on the color of yerba maté (Ilex paraguariensis) leaves

The aim of this work was to study the effect of alkaline blanching followed by an immersion in salt solutions of Mg2+, Cu2+ and Zn2+ on color preservation of Yerba Maté leaves. The concentration of NaOH in the alkaline solution influenced all of the color parameters. Ion concentration and dipped time influenced only some color parameters. The color parameters of the product obtained with different treatments were different from the control sample (blanched with boiling water instead of alkaline blanching) and from the product obtained via industrial processing. The green color in the pre-treated and control samples was more intense (greater values of -a) and darker (low values of L and b). Ionic and ash content in the leaves increased with the treatments