4,655 research outputs found
Retinoic Acid Differentially Regulates the Migration of Innate Lymphoid Cell Subsets to the Gut
SummaryDistinct groups of innate lymphoid cells (ILCs) such as ILC1, ILC2, and ILC3 populate the intestine, but how these ILCs develop tissue tropism for this organ is unclear. We report that prior to migration to the intestine ILCs first undergo a “switch” in their expression of homing receptors from lymphoid to gut homing receptors. This process is regulated by mucosal dendritic cells and the gut-specific tissue factor retinoic acid (RA). This change in homing receptors is required for long-term population and effector function of ILCs in the intestine. Only ILC1 and ILC3, but not ILC2, undergo the RA-dependent homing receptor switch in gut-associated lymphoid tissues. In contrast, ILC2 acquire gut homing receptors in a largely RA-independent manner during their development in the bone marrow and can migrate directly to the intestine. Thus, distinct programs regulate the migration of ILC subsets to the intestine for regulation of innate immunity
Improvement of a convertible undeniable partially blind signature scheme
Undeniable signatures are the digital signatures that should be verified with the help of the signer. A signer may disavow a genuine document, if the signature is only verifiable with the aid of the signer under the condition that the signer is not honest. Undeniable signatures solve this problem by adding a new feature called the disavowal protocol in addition to the normal components of signature and verification. Disavowal protocol is able to prevent a dishonest signer from disavowing a valid signature. In some situations, an undeniable signature should be converted into a normal digital signature in order that the signature can be universally verified. Blind signatures are the digital signatures that help a user to get a signature on a message without revealing the content of the message to a signer. For the blind signatures, if the signer is able to make an agreement with the user, then the underlying signer may include some common information that is known to the user, then such signatures are partially blind signatures. Convertible undeniable partially blind signatures are of the features of undeniable signatures, blind signatures, convertible undeniable signatures, and partially blind signatures. Recently, a convertible undeniable partially blind signature scheme was presented. In this paper, we first analyse a security flaw of the convertible undeniable partially blind signature scheme. To address the security flaw, we present an improvement on the disavowal protocol. The improved scheme can prevent the signer from either proving that a given valid signature as invalid, or cheating the verifier
A new proxy signature scheme as secure as EIGamal signature
Proxy signature helps the proxy signer to sign messages on behalf of the original signer. It is very useful when the original signer (e.g. the president of a company) is not available to sign a specific document. If the original signer can not forge valid proxy signatures through impersonating the proxy signer, it will be robust in a virtual environment; thus the original signer can not shift any illegal action initiated by herself to the proxy signer. In this paper, we propose a new proxy signature scheme. The new scheme can prevent the original signer from impersonating the proxy signer to sign messages. The proposed scheme is based on the regular ElGamal signature. In addition, the fair privacy of the proxy signer is maintained. That means, the privacy of the proxy signer is preserved; and the privacy can be revealed when it is necessary
A New Proxy Signature Scheme As Secure As ElGamal Signature
Proxy signature helps the proxy signer to sign messages on behalf of the original signer. It is very useful when the original signer (e.g. the president of a company) is not available to sign a specific document. If the original signer can not forge valid proxy signatures through impersonating the proxy signer, it will be robust in a virtual environment; thus the original signer can not shift any illegal action initiated by herself to the proxy signer. In this paper, we propose a new proxy signature scheme. The new scheme can prevent the original signer from impersonating the proxy signer to sign messages. The proposed scheme is based on the regular ElGamal signature. In addition, the fair privacy of the proxy signer is maintained. That means, the privacy of the proxy signer is preserved; and the privacy can be revealed when it is necessary
Morphologies of low-redshift AGN host galaxies: what role does AGN luminosity play?
Mergers of galaxies have been suspected to be a major trigger of AGN activity
for many years. However, when compared to carefully matched control samples,
AGN host galaxies often show no enhanced signs of interaction. A common
explanation for this lack of observed association between AGN and mergers has
often been that while mergers are of importance for triggering AGN, they only
dominate at the very high luminosity end of the AGN population. In this study,
we compare the morphologies of AGN hosts to a carefully matched control sample
and particularly study the role of AGN luminosity. We find no enhanced merger
rates in AGN hosts and also find no trend for stronger signs of disturbance at
higher AGN luminosities. While this study does not cover very high luminosity
AGN, we can exclude a strong connection between AGN and mergers over a wide
range of AGN luminosities and therefore for a large part of the AGN population.Comment: Proceedings of the conference "Nuclei of Seyfert galaxies and QSOs -
Central engine & conditions of star formation" held in Bonn, Germany, 201
A new encryption algorithm over elliptic curve
Various public key encryption systems have been proposed in modern information techology. Some of them have also been used in various applications, such as E-commerce and mobile database. This paper proposes two secure receipt oriented encryption systems. The decryptioner's private keys could be changed with the different time periods. This case would be very useful in some practical scenarios, for instance, in a mobile database environment. Besides the semantic security, the proposed schemes have the backward-and-future security, a new security requirement for semantically secure encryption schemes. In terms of construction, the two schemes are based on the pairings over elliptic curves. Also, this paper provides a heuristic security analysis for the underlying system
Shedding of PRRS Virus in Milk and Colostrum
Porcine reproductive and respiratory virus (PRRSV) is endemic in many swine herds. The means by which PRRSV continues to circulate in herds is not well understood. Under experimental conditions, we found that PRRSV is shed in the milk and colostrum of infected dams. Virus-contaminated mammary secretions could play an important role in virus transmission in endemically infected herds
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Systemic sclerosis is associated with specific alterations in gastrointestinal microbiota in two independent cohorts.
ObjectiveTo compare faecal microbial composition in patients with systemic sclerosis (SSc) from 2 independent cohorts with controls and to determine whether certain genera are associated with SSc-gastrointestinal tract (GIT) symptoms.DesignAdult patients with SSc from the University of California, Los Angeles (UCLA) and Oslo University Hospital (OUH) and healthy controls participated in this study (1:1:1). All participants provided stool specimens for 16S rRNA sequencing. Linear discriminant analysis effect size demonstrated genera with differential expression in SSc. Differential expression analysis for sequence count data identified specific genera associated with GIT symptoms as assessed by the GIT 2.0 questionnaire.ResultsThe UCLA-SSc and OUH-SSc cohorts were similar in age (52.1 and 60.5 years, respectively), disease duration (median (IQR): 6.6 (2.5-16.4) and 7.0 (1.0-19.2) years, respectively), gender distribution (88% and 71%, respectively), and GIT symptoms (mean (SD) total GIT 2.0 scores of 0.7 (0.6) and 0.6 (0.5), respectively). Principal coordinate analysis illustrated significant microbial community differences between SSc and controls (UCLA: p=0.001; OUH: p=0.002). Patients with SSc had significantly lower levels of commensal genera deemed to protect against inflammation, such as Bacteroides (UCLA and OUH), Faecalibacterium (UCLA), Clostridium (OUH); and significantly higher levels of pathobiont genera, such as Fusobacterium (UCLA), compared with controls. Increased abundance of Clostridium was associated with less severe GIT symptoms in both cohorts.ConclusionsThe present analysis detected specific aberrations in the lower GIT microbiota of patients with SSc from 2 geographically and ethnically distinct cohorts. These findings suggest that GIT dysbiosis may be a pathological feature of the SSc disease state
Bright Fluorescent Chemosensor Platforms for Imaging Endogenous Pools of Neuronal Zinc
AbstractA series of new fluorescent Zinpyr (ZP) chemosensors based on the fluorescein platform have been prepared and evaluated for imaging neuronal Zn2+. A systematic synthetic survey of electronegative substitution patterns on a homologous ZP scaffold provides a basis for tuning the fluorescence responses of “off-on” photoinduced electron transfer (PET) probes by controlling fluorophore pKa values and attendant proton-induced interfering fluorescence of the metal-free (apo) probes at physiological pH. We further establish the value of these improved optical tools for interrogating the metalloneurochemistry of Zn2+; the novel ZP3 fluorophore images endogenous stores of Zn2+ in live hippocampal neurons and slices, including the first fluorescence detection of Zn2+ in isolated dentate gyrus cultures. Our findings reveal that careful control of fluorophore pKa can minimize proton-induced fluorescence of the apo probes and that electronegative substitution offers a general strategy for tuning PET chemosensors for cellular studies. In addition to providing improved optical tools for Zn2+ in the neurosciences, these results afford a rational starting point for creating superior fluorescent probes for biological applications
Manipulations of List Type in the DRM Paradigm: A Review of How Structural and Conceptual Similarity Affect False Memory
The use of list-learning paradigms to explore false memory has revealed several critical findings about the contributions of similarity and relatedness in memory phenomena more broadly. Characterizing the nature of “similarity and relatedness” can inform researchers about factors contributing to memory distortions and about the underlying associative and semantic networks that support veridical memory. Similarity can be defined in terms of semantic properties (e.g., shared conceptual and taxonomic features), lexical/associative properties (e.g., shared connections in associative networks), or structural properties (e.g., shared orthographic or phonological features). By manipulating the type of list and its relationship to a non-studied critical item, we review the effects of these types of similarity on veridical and false memory. All forms of similarity reviewed here result in reliable error rates and the effects on veridical memory are variable. The results across a variety of paradigms and tests provide partial support for a number of theoretical explanations of false memory phenomena, but none of the theories readily account for all results
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