553 research outputs found

    Do personal conditions and circumstances surrounding partner loss explain loneliness in newly bereaved older adults?

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    This longitudinal study aims to explain loneliness in newly bereaved older adults, taking into account personal and circumstantial conditions surrounding the partner's death. A distinction is made between emotional and social loneliness. Data were gathered both before and after partner loss. Results were interpreted within the framework of the Theory of Mental Incongruity. The findings reveal that being unable to anticipate the partner's death is related to higher levels of emotional loneliness. Standards of instrumental support, measured indirectly by poor physical condition, lead to stronger emotional as well as social loneliness. Standards measured directly by importance attached to support or contacts result in higher emotional loneliness but, unexpectedly, in lower social loneliness. Furthermore, difficulties with establishing personal contacts, caused, for instance, by social anxiety, add to loneliness. It is concluded that circumstances related to the partner's illness may contribute to emotional loneliness after bereavement. Moreover, the results highlight the importance of taking coping attitudes into consideration for a better understanding of how newly bereaved older adults adapt to the loss of a partner

    Heterogeneous expression pattern of interleukin 17A (IL-17A), IL-17F and their receptors in synovium of rheumatoid arthritis, psoriatic arthritis and osteoarthritis: possible explanation for nonresponse to anti-IL-17 therapy?

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    Accumulating evidence suggests an important role for interleukin 17 (IL-17) in the pathogenesis of several inflammatory diseases, including rheumatoid arthritis (RA) and psoriatic arthritis (PsA). Accordingly, clinical trials aimed at blocking IL-17 have been initiated, but clinical results between patients and across different diseases have been highly variable. The objective was to determine the variability in expression of IL-17A, IL-17F and their receptors IL-17RA and IL-17RC in the synovia of patients with arthritis. Synovial biopsies were obtained from patients with RA (n = 11), PsA (n = 15) and inflammatory osteoarthritis (OA, n = 14). For comparison, synovia from noninflamed knee joints (n = 7) obtained from controls were included. Frozen sections were stained for IL-17A, IL-17F, IL-17RA and IL-17RC and evaluated by digital image analysis. We used confocal microscopy to determine which cells in the synovium express IL-17A and IL-17F, double-staining with CD4, CD8, CD15, CD68, CD163, CD31, von Willebrand factor, peripheral lymph node address in, lymphatic vessel endothelial hyaluronan receptor 1, mast cell tryptase and retinoic acid receptor-related orphan receptor γt (RORγt). IL-17A, IL-17F, IL-17RA and IL-17RC were abundantly expressed in synovial tissues of all patient groups. Whereas IL-17RA was present mostly in the synovial sublining, IL-17RC was abundantly expressed in the intimal lining layer. Digital image analysis showed a significant (P  < 0.05) increase of only IL-17A in arthritis patients compared to noninflamed control tissues. The expression of IL-17A, IL-17F and their receptors was similar in the different patient groups, but highly variable between individual patients. CD4+ and CD8+ cells coexpressed IL-17A, and few cells coexpressed IL-17F. IL-17A and IL-17F were not expressed by CD15+ neutrophils. Mast cells were only occasionally positive for IL-17A or IL-17F. Interestingly, IL-17A and IL-17F staining was also observed in macrophages, as well as in blood vessels and lymphatics. This staining probably reflects receptor-bound cytokine staining. Many infiltrated cells were positive for the transcription factor RORγt. Colocalisation between RORγt and IL-17A and IL-17F indicates local IL-17 production. Increased expression of IL-17A is not restricted to synovial tissues of RA and PsA patients; it is also observed in inflammatory OA. The heterogeneous expression levels may explain nonresponse to anti-IL-17 therapy in subsets of patient

    Imaginary Quadratic Class Groups and a Survey of Time-Lock Cryptographic Applications

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    Imaginary quadratic class groups have been proposed as one of the main hidden-order group candidates for time-lock cryptographic applications such as verifiable delay functions (VDFs). They have the advantage over RSA groups that they do \emph{not} need a trusted setup. However, they have historically been significantly less studied by the cryptographic research community. This survey provides an introduction to the theory of imaginary quadratic class groups and discusses several considerations that need to be taken into account for practical applications. In particular, we describe the relevant computational problems and the main classical and quantum algorithms that can be used to solve them. From this discussion, it follows that choosing a discriminant Δ=p\Delta=-p with p3mod4p\equiv 3\mod{4} prime is one of the most promising ways to pick a class group \CL(\Delta) without the need for a trusted setup, while simultaneously making sure that there are no easy to find elements of low order in \CL(\Delta). We provide experimental data on class groups belonging to discriminants of this form, and compare them to the Cohen-Lenstra heuristics which predict the average behaviour of \CL(\Delta) belonging to a random \emph{fundamental} discriminant. Afterwards, we describe the most prominent constructions of VDFs based on hidden-order groups, and discuss their soundness and sequentiality when implemented in imaginary quadratic class groups. Finally, we briefly touch upon the post-quantum security of VDFs in imaginary quadratic class groups, where the time on can use a fixed group is upper bounded by the runtime of quantum polynomial time order computation algorithms

    Fuzzy Private Set Intersection with Large Hyperballs

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    Traditional private set intersection (PSI) involves a receiver and a sender holding sets XX and YY, respectively, with the receiver learning only the intersection XYX\cap Y. We turn our attention to its fuzzy variant, where the receiver holds X|X| hyperballs of radius δ\delta in a metric space and the sender has Y|Y| points. Representing the hyperballs by their center, the receiver learns the points xXx\in X for which there exists yYy\in Y such that dist(x,y)δ\mathsf{dist}(x,y)\leq \delta with respect to some distance metric. Previous approaches either require general-purpose multi-party computation (MPC) techniques like garbled circuits or fully homomorphic encryption (FHE), leak details about the sender’s precise inputs, support limited distance metrics, or scale poorly with the hyperballs\u27 volume. This work presents the first black-box construction for fuzzy PSI (including other variants such as PSI cardinality, labeled PSI, and circuit PSI), which can handle polynomially large radius and dimension (i.e., a potentially exponentially large volume) in two interaction messages, supporting general Lp[1,]L_{p\in[1,\infty]} distance, without relying on garbled circuits or FHE. The protocol excels in both asymptotic and concrete efficiency compared to existing works. For security, we solely rely on the assumption that the Decisional Diffie-Hellman (DDH) holds in the random oracle model

    Amortizing Circuit-PSI in the Multiple Sender/Receiver Setting

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    Private set intersection (PSI) is a cryptographic functionality for two parties to learn the intersection of their input sets, without leaking any other information. Circuit-PSI is a stronger PSI functionality where the parties learn only a secret-shared form of the desired intersection, thus without revealing the intersection directly. These secret shares can subsequently serve as input to a secure multiparty computation of any function on this intersection. In this paper we consider several settings in which parties take part in multiple Circuit-PSI executions with the same input set, and aim to amortize communications and computations. To that end, we build up a new framework for Circuit-PSI around generalizations of oblivious (programmable) PRFs that are extended with offline setup phases. We present several efficient instantiations of this framework with new security proofs for this setting. As a side result, we obtain a slight improvement in communication and computation complexity over the state-of-the art Circuit-PSI protocol by Bienstock et al. (USENIX \u2723). Additionally, we present a novel Circuit-PSI protocol from a PRF with secret-shared outputs, which has linear communication and computation complexity in the parties\u27 input set sizes, and incidentally, it realizes ``almost malicious\u27\u27 security, making it the first major step in this direction since the protocol by Huang et al. (NDSS \u2712). Lastly, we derive the potential amortizations over multiple protocol executions, and observe that each of the presented instantiations is favorable in at least one of the multiple-execution settings

    Amortizing Circuit-PSI in the Multiple Sender/Receiver Setting

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    Private set intersection (PSI) is a cryptographic functionality for two parties to learn the intersection of their input sets, without leaking any other information. Circuit-PSI is a stronger PSI functionality where the parties learn only a secret-shared form of the desired intersection, thus without revealing the intersection directly. These secret shares can subsequently serve as input to a secure multiparty computation of any function on this intersection.In this paper we consider several settings in which parties take part in multiple Circuit-PSI executions with the same input set, and aim to amortize communications and computations. To that end, we build up a new framework for Circuit-PSI around generalizations of oblivious (programmable) PRFs that are extended with offline setup phases. We present several efficient instantiations of this framework with new security proofs for this setting. As a side result, we obtain a slight improvement in communication and computation complexity over the state-of-the-art semi-honest Circuit-PSI protocol by Bienstock et al. (USENIX \u2723). Additionally, we present a novel Circuit-PSI protocol from a PRF with secret-shared outputs, which has linear communication and computation complexity in the parties\u27 input set sizes, and is able to realize a stronger security notion. Lastly, we derive the potential amortizations over multiple protocol executions, and observe that each of the presented instantiations is favorable in at least one of the multiple-execution settings. </p

    Fuzzy Private Set Intersection from VOLE

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    Private set intersection (PSI) is a well-researched cryptographic primitive that allows two parties to compute the intersection of their input sets without revealing any information about items outside of the intersection. Fuzzy private set intersection is a relatively new variant of PSI, where items are not matched exactly but ``fuzzily\u27\u27. Most commonly, items are points q,w\mathbf{q},\mathbf{w} in dd-dimensional integer space Zd\mathbb{Z}^d and a point is a fuzzy match to another if it lies within a ball of radius δ\delta centered at this point, with respect to some distance metric. Previous works either only support infinity (L(L_{\infty}) distance metric and standard PSI functionality, or support general Minkowski (LpL_{\mathsf{p}}, p[1,]\mathsf{p}\in[1,\infty]) distance metrics and realize richer functionalities but rely on expensive homomorphic encryptions. Our work aims to bridge this gap by giving the first construction of a fuzzy PSI protocol for general Minkowski distance metrics relying on significantly cheaper operations during the online phase. Our main building block is a novel fuzzy matching protocol based on an oblivious pseudorandom function (OPRF), which can be realized very efficiently from vector oblivious linear evaluation (VOLE). Our protocol is able to preserve the asymptotic complexity as well as the simplicity of the fuzzy matching protocol from van Baarsen and Pu (Eurocrypt \u2724), while being much more concretely efficient. Additionally, we achieve several asymptotic improvements by representing intervals succinctly. Finally, we present the first fuzzy PSI protocol for infinity distance that places no assumptions on the sets of points, while maintaining asymptotic complexities comparable to the state-of-the-art fuzzy PSI protocol
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