| 44921. |
- Kuzume, A., et al.
(författare)
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Electrochemical reactivity in nanoscale domains: O-2 reduction on a fullerene modified gold surface
- 2005
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Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 7:6, s. 1293-1299
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Tidskriftsartikel (refereegranskat)abstract
- Fullerene is strongly adsorbed on both single crystal and polycrystalline gold surfaces and its specific adsorption resulted in the formation of high coverage large hexagonal rafts with strong interactions between the adsorbed fullerene molecules and the Au substrate. The oxygen reduction reaction (ORR) was investigated on these surfaces to determine their influence on the reduction mechanism. Oxygen reduction did not take place on the fullerene overlayer but proceeded on the sub-nanometer sized exposed pockets of the underlying Au substrate. Reduction at these confined sites produces hydrogen peroxide selectively. This effect is ascribed to the blocking action, or so-called "third body effect'', of the adsorbed fullerene molecules, which do not display electrocatalytic properties for oxygen reduction.
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| 44922. |
- Kvaerner, A. S., et al.
(författare)
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The CRCbiome study: a large prospective cohort study examining the role of lifestyle and the gut microbiome in colorectal cancer screening participants
- 2021
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Ingår i: Bmc Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Colorectal cancer (CRC) screening reduces CRC incidence and mortality. However, current screening methods are either hampered by invasiveness or suboptimal performance, limiting their effectiveness as primary screening methods. To aid in the development of a non-invasive screening test with improved sensitivity and specificity, we have initiated a prospective biomarker study (CRCbiome), nested within a large randomized CRC screening trial in Norway. We aim to develop a microbiome-based classification algorithm to identify advanced colorectal lesions in screening participants testing positive for an immunochemical fecal occult blood test (FIT). We will also examine interactions with host factors, diet, lifestyle and prescription drugs. The prospective nature of the study also enables the analysis of changes in the gut microbiome following the removal of precancerous lesions. Methods: The CRCbiome study recruits participants enrolled in the Bowel Cancer Screening in Norway (BCSN) study, a randomized trial initiated in 2012 comparing once-only sigmoidoscopy to repeated biennial FIT, where women and men aged 50-74 years at study entry are invited to participate. Since 2017, participants randomized to FIT screening with a positive test result have been invited to join the CRCbiome study. Self-reported diet, lifestyle and demographic data are collected prior to colonoscopy after the positive FIT-test (baseline). Screening data, including colonoscopy findings are obtained from the BCSN database. Fecal samples for gut microbiome analyses are collected both before and 2 and 12 months after colonoscopy. Samples are analyzed using metagenome sequencing, with taxonomy profiles, and gene and pathway content as primary measures. CRCbiome data will also be linked to national registries to obtain information on prescription histories and cancer relevant outcomes occurring during the 10 year follow-up period. Discussion: The CRCbiome study will increase our understanding of how the gut microbiome, in combination with lifestyle and environmental factors, influences the early stages of colorectal carcinogenesis. This knowledge will be crucial to develop microbiome-based screening tools for CRC. By evaluating biomarker performance in a screening setting, using samples from the target population, the generalizability of the findings to future screening cohorts is likely to be high.
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| 44923. |
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| 44924. |
- Kvarnstrand, John, et al.
(författare)
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Comparison of live person test to head and hand phantom test in reverberation chamber
- 2016
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Ingår i: 2016 10th European Conference on Antennas and Propagation (EuCAP).
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Konferensbidrag (refereegranskat)abstract
- The Total Radiated Power of a cell phone was measured in a reverberation chamber with a head and hand phantom and compared to live person testing of 5 test subjects who held device in similar grip as the phantom. Repeatability in tests was examined for the phantom and for the live person test subjects. The method demonstrated can be used to evaluate mobile devices handled by live persons. It can also be used to validate that a phantom is a good representation of live persons.
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| 44925. |
- Kvarnström, Elisabeth, et al.
(författare)
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Sanitation Planning : A Tool to Achieve Sustainable Sanitation?
- 2007
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Ingår i: Proceedings of Water Supply and Sanitation For All.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The global sanitation crisis and its importance to the Millennium Development Goals (MDGs) is reflected in the specific sanitation target adopted in 2002. An enormous amount of funds will need to be invested in sanitation over the coming years in order to meet the MDGs. It is important that these funds are invested in sustainable sanitation systems, since providing sanitation systems that are not sustained is a very costly shortterm solution that may contribute to long-term problems. The authors strongly believe that sanitation planning is one key to sustainable sanitation. Recent planning frameworks for sustainable sanitation systems suggest the utilization of a number of steps: (i) recognizing the existence of different domains across the city, (ii) analysis of the interests driving desire for the sanitation system and services for the stakeholders across the domains, (iii) analysis of external drivers and context that impact behaviour in each domain (iv) analysis of technical options, in relation to findings on context and criteria, (v) analysis of management requirements for proposed technical options, (vi) critical assessment whether the proposed system is fit for the purpose. This paper will discuss the merits and challenges of these planning methodologies in reference to experience from West Africa and Sweden. The intent is to illustrate the potential of these methods for increasing sustainable sanitation, but also to raise some key questions that may be missing from the frameworks.
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| 44926. |
- Kvarnström, Elisabeth, et al.
(författare)
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The Sanitation Ladder – a Need for a Revamp?
- 2011
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Ingår i: Journal of Water Sanitation and Hygiene for Development. - : IWA Publishing. - 2043-9083 .- 2408-9362. ; 1:1, s. 3-12
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Tidskriftsartikel (refereegranskat)abstract
- The sanitation ladder is a useful tool that is being used to monitor progress towards the sanitation target of the MDGs. This tool could be even more useful if it can be refined to be based on the functions of sanitation systems rather than on a hierarchy of predefined sanitation technologies. This paper presents a seven-rung function-based sanitation ladder where the functions can be broadly divided into health functions and environmental functions. The proposed ladder is intended as an inspiration for nations, and the JMP, to move towards a function-based rather than technology-based monitoring of sanitation progress. A functional approach to monitoring of e.g. the sanitation target of the MDGs would require some major shifts in the monitoring methods used but it is argued that such an approach would: (i) actually monitor the public good, which is desired from a sanitation system; (ii) stimulate donors, governments and municipalities to think beyond the provision of certain sanitation technologies; (iii) allow for local solutions to the sanitation problem to be developed; and (iv) spur innovation within the sector.
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| 44927. |
- Kvarnström, Håkan, 1968, et al.
(författare)
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A Protection Scheme For Security Policies In Ubiquitous Environments Using One-Way Functions
- 2002
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Ingår i: UBICOMP2002 - Workshop on Security in Ubiquitous Computing, Göteborg, 29 September 2002.
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Konferensbidrag (refereegranskat)abstract
- This paper addresses the problem of protecting security policies and other security-related information in security mechanisms and products, such as the detection policy in an Intrusion Detection System (IDS) or the filtering policy in a firewall. Unauthorized disclosure of the such information is particularly serious, since it might reveal the fundamental principles and methods for the security and protection of the whole system or network, which is much more far-reaching that the protection of the target system or security mechanism itself. This problem is especially noticeable in ubiquitous environments where a possible large number of nodes need knowledge about the security policy of their domain. In order to avoid this risk we suggest that security information should be protected using one-way functions and the paper suggests a basic scheme for protecting stateless policies. A stateless policy is a policy that only takes the current event into consideration when decisions are made and not the preceding chain of events. Thus, the process of comparing events towards the policy, i.e. making decisions, could be done in much the same way that passwords are hashed and compared in UNIX systems. However, one important distinction is that security policies contain a certain variability that must be handled and a method for this is discussed. The suggested scheme is very basic and has certain drawbacks as regards practical implementation, but does still clearly demonstrate the protection principle. We expect further research to result in extended methods that are more suitable for practical design.
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| 44928. |
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| 44929. |
- Kvarnström, Håkan, 1968
(författare)
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On the Implementation and Protection of Fraud Detection Systems
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Society of today is becoming increasingly dependent on the availability and correctness of IT-systems. There are a growing number of industries that base their business almost exclusively on creating growth and economic value using IT-systems. Banks, credit card providers, online gambling brokers and providers of telecommunication services are a few examples where secure and reliable communication and computing environments are of the outmost importance for survival. These new services can create increased customer value and provide new business opportunities. However, history shows that fraudsters constantly seek economic gain by exploiting weaknesses in technical systems or business models of service offerings. Thus, minimizing economic loss due to fraud is an important goal in many enterprises. An important tool in that process is an efficient fraud detection system (FDS) that can give early indications of misuse of products and services offered to customers. This thesis addresses the subject of implementing and protecting an FDS. Specifically, we give arguments for the importance of thorough testing, training and sufficient protection when deploying a successful fraud detection system. We show how emerging computing environments put new demands on the security mechanisms and security extensions that protect the information and resources of their target environment. Fraud detection systems are no exception and we argue that detection mechanisms will play an important role in such environments. We propose and implement a methodology for generating synthetic data sets that can be used for testing and training fraud detection systems prior to real-life deployment. A comparison of fraud and intrusion detection system is made, where we highlight differences and similarities. Our study shows that the similarities clearly outweigh the differences, and research in one area is most often applicable for both types of systems. Finally, we discuss the topic of protecting fraud detection systems from malicious environments. Specifically, we study the importance of such systems from reverse engineering and propose mechanisms for achieving secrecy of the inherent information, even when deployed in hostile environments.
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| 44930. |
- Kvarnström, Håkan, 1968, et al.
(författare)
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Protecting Security Policies in Ubiquitous Environments Using One-Way Functions
- 2004
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Ingår i: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - 1611-3349 .- 0302-9743. - 3540208879 ; 2802, s. 71-85
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Konferensbidrag (refereegranskat)abstract
- This paper addresses the problem of protecting security policies and other security-related information in security mechanisms, such as the detection policy of an Intrusion Detection System or the filtering policy of a firewall. Unauthorized disclosure of such information can reveal the fundamental principles and methods for the protection of the whole network, especially in ubiquitous environments where a large number of nodes store knowledge about the security policy of their domain. To avoid this risk we suggest a scheme for protecting stateless security policies using one-way functions. A stateless policy is one that only takes into consideration, the current event, and not the preceding chain of events, when decisions are made. The scheme has a simple and basic design but can still be used for practical implementations, as illustrated in two examples in real-life enviroments. Further research aims to extend the scheme to stateful policies.
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