260 research outputs found

    Secure key storage with PUFs

    Get PDF
    Nowadays, people carry around devices (cell phones, PDAs, bank passes, etc.) that have a high value. That value is often contained in the data stored in it or lies in the services the device can grant access to (by using secret identification information stored in it). These devices often operate in hostile environments and their protection level is not adequate to deal with that situation. Bank passes and credit cards contain a magnetic stripe where identification information is stored. In the case of bank passes, a PIN is additionally required to withdraw money from an ATM (Automated Teller Machine). At various occasions, it has been shown that by placing a small coil in the reader, the magnetic information stored in the stripe can easily be copied and used to produce a cloned card. Together with eavesdropping the PIN (by listening to the keypad or recording it with a camera), an attacker can easily impersonate the legitimate owner of the bank pass by using the cloned card in combination with the eavesdropped PIN

    Satisfactory cross cultural equivalence of the Dutch WOMAC in patients with hip osteoarthritis waiting for arthroplasty

    Get PDF
    Background: Cross cultural validity is of vital importance for international comparisons. Objective: To investigate the validity of international Dutch-English comparisons when using the Dutch translation of the Western Ontario and McMaster Universities osteoarthritis index (WOMAC). Patients and Methods: The dimensionality, reliability, construct validity, and cross cultural equivalence of the Dutch WOMAC in Dutch and Canadian patients waiting for primary total hip arthroplasty was investigated. Unidimensionality and cross cultural equivalence was quantified by principal component and Rasch analysis. Intratest reliability was quantified with Cronbach's α, and test-retest reliability with the intraclass correlation coefficient. Construct validity was quantified by correlating sum scores of the Dutch WOMAC, Arthritis Impact Measurement Scales (Dutch AIMS2), Health Assessment Questionnaire (Dutch HAQ), and Harris Hip Score (Dutch HHS). Results: The WOMAC was completed by 180 Dutch and 244 English speaking Canadian patients. Unidimensionality of the Dutch WOMAC was confirmed by principal component and Rasch analysis (good fit for 20/22 items). The intratest reliability of the Dutch WOMAC for pain and physical functioning was 0.88 and 0.96, whereas the test-retest reliability was 0.77 and 0.92, respectively. Dutch WOMAC pain sum score correlated 0.69 with Dutch HAQ pain, and 0.39 with Dutch HHS pain. Dutch WOMAC physical functioning sum score correlated 0.46 with Dutch AIMS2 mobility, 0.62 with Dutch AIMS2 walking and bending, 0.67 with Dutch HAQ disability, and 0.49 with Dutch HHS function. Differential item functioning (DIF) was shown for 6/22 Dutch items. Conclusions: The Dutch WOMAC permits valid international Dutch-English comparisons after correction for DIF

    No increased mortality risk in older persons with unexplained anaemia

    Get PDF
    Background: in older persons, anaemia is associated with a number of unfavourable outcomes. In approximately 30% of older persons with anaemia, the cause of the anaemia is unexplained. We assessed the clinical differences between subjects with explained and unexplained anaemia and investigated whether these subjects have different mortality patterns compared with subjects without anaemia.Design: observational prospective follow-up study.Setting: the Leiden 85-plus study.Participants: four hundred and ninety-one persons aged 86 years.Methods: the study population was divided in three groups: (i) no anaemia (reference group, n = 377), (ii) explained anaemia (iron deficiency, folate deficiency, vitamin B12 deficiency, signs of myelodysplastic syndrome or renal failure, n = 74) and (iii) unexplained anaemia, (n = 40). Mortality risks were estimated with Cox-proportional hazard models.Results: haemoglobin levels were significantly lower in subjects with explained anaemia than in subjects with unexplained anaemia (P < 0.01). An increased risk for mortality was observed in subjects with explained anaemia [HR: 1.93 (95% CI: 1.47-2.52), P < 0.001], but not in subjects with unexplained anaemia [HR: 1.19 (95% CI: 0.85-1.69), P = 0.31]. Adjusted analyses (sex, co-morbidity, MMSE, institutionalised and smoking) did not change the observed associations for both explained and unexplained anaemic subjects.Conclusion: older subjects with unexplained anaemia had similar survival compared with non-anaemic subjects. Increased mortality risks were observed in subjects with explained anaemia compared with non-anaemic subjects.Public Health and primary careGeriatrics in primary car

    Stabilised aluminium phosphate nanoparticles used as vaccine adjuvant

    Get PDF
    Aluminium phosphate is a commonly used adjuvant consisting of heterogeneously sized aggregates up to several micrometers. However, aluminium phosphate nanoparticles may exhibit an improved adjuvant effect. In this study, nanoparticles were made by sonication of commercially available aluminium phosphate adjuvant, resulting in particles with a size (Z-average diameter) between 200-300 nm and a point of zero charge of 4.5. To prevent reaggregation, which occurred within 14 days, a screening of excipients was performed to identify stabilisers effective under physiological conditions (pH 7.4, 290 mOsm). The amino acids threonine, asparagine, and L-alanyl-L-1-aminoethylphosphonic acid (LAPA) stabilised sonicated aluminium phosphate. Particle sizes remained stable between 400-600 nm at 37 °C during 106 days. Contrarily, arginine induced strong reaggregation to a particle size larger than 1000 nm. The stability of aluminium phosphate nanoparticles was strongly affected by the pH. Aggregation mainly occurred below pH 7. The adsorption capacity, a potentially relevant parameter for adjuvants, was slightly reduced in the presence of asparagine, when using a model antigen (lysozyme). LAPA, arginine, threonine and aspartic acid reduced protein adsorption significantly. The adjuvant effect of aluminium phosphate nanoparticles was studied by immunisation of mice with diphtheria toxoid adjuvanted with the aluminium phosphate nanoparticles. The presence of LAPA, threonine, aspartic acid or asparagine did not alter diphtheria toxoid-specific antibody or toxin-neutralising antibody titres. Arginine increased diphtheria toxoid-specific antibody titres but not toxin-neutralising antibody titres. In conclusion, aluminium phosphate nanoparticles were stabilised by particular amino acids and induced an adjuvant effect comparable to that of aluminium phosphate microparticles.Drug Delivery Technolog

    Influence of spark ignition in the determination of Markstein lengths using spherically expanding flames

    Get PDF
    Constant pressure outwardly propagating flame experiments in a spherical bomb are performed to examine the duration and radius over which spark ignition effects persist. This is motivated by the need to properly account for such effects in the measurement of laminar burning velocity and Markstein length using the spark ignited expanding flame technique. Ignition energy was varied and its effects on flame propagation in methane-air and isooctane-air mixtures were studied. The Markstein length of the mixture proved critical in the ignition energy dependency of flame propagation. For relatively high values, an underlying common variation of self-sustaining flame speed with radius can be identified by the rapid convergence of curves for different ignition energies. As the Markstein length decreases, low energy spark ignition is found to give rise to a distorted and wrinkled flame kernel. For such mixtures, due to the weak effect of stretch, the kernel subsequently develops into a non-spherically propagating flame. In these cases the spark ignition effect persists up to large radius. It is shown that using low ignition energy leads to a flame speed, during the development phase, which is higher than that of a self-sustaining spherical flame. It is further shown that if this effect is not accounted for, measurements of Markstein length using standard fitting techniques results in a large error. This problem is found to worsen as the Markstein length decreases, such that its apparent measured value becomes increasingly influenced by any distortions of the flame kernel produced by the spark

    Circulating immunoglobulins are not associated with intraplaque mast cell number and other vulnerable plaque characteristics in patients with carotid artery stenosis.

    Get PDF
    BACKGROUND\nRecently, we have shown that intraplaque mast cell numbers are associated with atherosclerotic plaque vulnerability and with future cardiovascular events, which renders inhibition of mast cell activation of interest for future therapeutic interventions. However, the endogenous triggers that activate mast cells during the progression and destabilization of atherosclerotic lesions remain unidentified. Mast cells can be activated by immunoglobulins and in the present study, we aimed to establish whether specific immunoglobulins in plasma of patients scheduled for carotid endarterectomy were related to (activated) intraplaque mast cell numbers and plasma tryptase levels. In addition, the levels were related to other vulnerable plaque characteristics and baseline clinical data.\nMETHODS AND RESULTS\nOxLDL-IgG, total IgG and total IgE levels were measured in 135 patients who underwent carotid endarterectomy. No associations were observed between the tested plasma immunoglobulin levels and total mast cell numbers in atherosclerotic plaques. Furthermore, no associations were found between IgG levels and the following plaque characteristics: lipid core size, degree of calcification, number of macrophages or smooth muscle cells, amount of collagen and number of microvessels. Interestingly, statin use was negatively associated with plasma IgE and oxLDL-IgG levels.\nCONCLUSIONS\nIn patients suffering from carotid artery disease, total IgE, total IgG and oxLDL-IgG levels do not associate with plaque mast cell numbers or other vulnerable plaque histopathological characteristics. This study thus does not provide evidence that the immunoglobulins tested in our cohort play a role in intraplaque mast cell activation or grade of atherosclerosis.Biopharmaceutic
    • …
    corecore