78 research outputs found
Social Networks Privacy-Preserving On Collaborative Tagging and Spam Filter Using Naive Bayes Algorithm
ABSTRACT: Collaborative tagging is one of the most popular services available in social networks, and it allows user to classify either online or offline resources based on their feedback, deliver in the form of tags. Although tags may not be secret information the wide use of collaborative tagging services increases the risk, thereby seriously compromising user privacy. In this paper, we make a contribution towards the development of a privactivey-preserving collaborative tagging service, by showing how a specific privacy-enhancing technology, namely tag suppression, can be used to protect end-user privacy.In most group key management protocols, group members are authenticated by the group leader "one by one." That is, n authentication messages are required to authenticate n group members. Then, these members share one common group key for the group communication. In our batch authentication protocols, users are simultaneously authenticated by the requester that is, one authentication message is required to authenticate n session peers.Spam is commonly defined as irrelevant comments or text, the goal of spam is to distinguish between irrelevant and relevant comments. Naive Bayes classifiers are among the most successful known algorithms for learning to classify text documents.Bayesian spam filtering has become a popular mechanism to distinguish illegitimate spam texts from legitimate text
Recent trends and developments in pyrolysis-gas chromatography: review
Pyrolysis-gas chromatography (Py-GC) has become well established as a simple, quick and reliable analytical technique for a range of applications including the analysis of polymeric materials. Recent developments in Py-GC technology and instrumentation include laser pyrolysis and non-discriminating pyrolysis. Progress has also been made in the detection of low level polymer additives with the use of novel Py-GC devices. Furthermore, it has been predicted that future advances in separation technology such as the use of comprehensive two-dimensional gas chromatography will further enhance the analytical scope of Py-GC
How Contemporary Human Reproductive Behaviors Influence the Role of Fertility-Related Genes: The Example of the P53 Gene
Studies on human fertility genes have identified numerous risk/protective alleles involved in the occurrence of reproductive system diseases causing infertility or subfertility. Investigations we carried out in populations at natural fertility seem to suggest that the clinical relevance that some fertility genes are now acquiring depends on their interaction with contemporary reproductive behaviors (birth control, delayed childbearing, and spacing birth order, among others). In recent years, a new physiological role in human fertility regulation has emerged for the tumor- suppressor p53 gene (P53), and the P53 Arg72Pro polymorphism has been associated with recurrent implantation failure in humans. To lend support to our previous observations, we examined the impact of Arg72Pro polymorphism on fertility in two samples of Italian women not selected for impaired fertility but collected from populations with different (premodern and modern) reproductive behaviors. Among the women at near-natural fertility (n = 98), the P53 genotypes were not associated with different reproductive efficiency, whereas among those with modern reproductive behaviors (n = 68), the P53 genotypes were associated with different mean numbers of children [Pro/Pro = 0.75<Pro/Arg = 1.7<Arg/Arg = 2, (p = 0.056)] and a significant negative relationship between the number of children and P53 Pro allele frequencies (p = 0.028) was observed. These results are consistent with those of clinical studies reporting an association between the P53 Pro allele and recurrent implantation failure. By combining these findings with previous ones, we suggest here that some common variants of fertility genes may have become “detrimental” following exposure to modern reproductive patterns and might therefore be associated with reduced reproductive success. Set within an evolutionary framework, this change could lead to the selection of a set of gene variants fitter to current reproductive behaviors as the shift to later child-bearing age in developed countries
Potential Role of Aromatase over Estrogen Receptor Gene Polymorphisms in Migraine Susceptibility: A Case Control Study from North India
BACKGROUND: The present study was undertaken to find out the role of estrogen pathway related gene polymorphisms in susceptibility to migraine in Northern Indian population. Aromatase, CYP19A1 (rs10046 and rs4646); estrogen receptors, ESR1 (rs2234693, rs1801132, rs2228480 and rs9340799) and ESR2 (rs1271572 and rs1256049) polymorphisms were selected for the present study. METHODOLOGY/PRINCIPAL FINDINGS: The patients were recruited in two cohorts - primary (207) and replicative (127) along with 200 healthy controls and genotyped for various polymorphisms. Logistic regression analysis was applied for statistical analyses. The results were validated in the replicative cohort and pooled by meta analysis using Fisher's and Mantel-Haenszel test. Furthermore, Benjamini - Hochberg false discovery rate test was used to correct for multiple comparisons. CYP19A1 rs10046 and CYP19A1 rs4646 polymorphisms were found to confer risk and protective effect, respectively. Out of four ESR1 polymorphisms, only rs2234693 variant allele was significantly associated in migraine with aura. No significant associations were observed for ESR2 polymorphisms. Significant haplotypes were identified for CYP19A1 and ESR1 polymorphisms. Gene- gene interactions of genotypes as well as haplotypes were observed for CYP19A1- ESR1 showing both risk and protective combinations. CONCLUSION: We strongly suggest CYP19A1 polymorphisms to be the major contributing factors in migraine susceptibility instead of genetic variants of estrogen receptors
Estrogen Receptor-Beta Gene Polymorphism in women with Breast Cancer at the Imam Khomeini Hospital Complex, Iran
ER-alpha and ER-beta genes have been proven to play a significant role in breast cancer. Epidemiologic studies have revealed that age-incidence patterns of breast cancer in Middle East differ from those in the Western countries. Two selected coding regions in the ER-β gene (exons 3 and 7) were scanned in Iranian women with breast cancer (150) and in healthy individuals (147). PCR single-strand conformation polymorphism was performed. A site of silent single nucleotide polymorphism was found only on exon 7. The SNP was found only in breast cancer patients (5.7%) (χ2 = 17.122, P = 0.01). Codon 392 (C1176G) of allele 1 was found to have direct association with the occurrence of lymph node metastasis. Our data suggest that ER-β polymorphism in exon 7 codon 392 (C1176G) is correlated with various aspects of breast cancer and lymph node metastasis in our group of patients
Effects of two common polymorphisms in the 3' untranslated regions of estrogen receptor β on mRNA stability and translatability
Estrogen signaling is mediated by estrogen receptors (ERs), ERα and ERβ. Aberrant
estrogen signaling is involved in breast cancer development. ERα is one of the key
biomarkers for diagnosis and treatment of breast cancer. Unlike ERα, ERβ is still not
introduced as a marker for diagnosis and established as a target of therapy. Numerous
studies suggest antiproliferative effects of ERβ, however its role remains to be fully
explored. Albeit important, ERα is not a perfect marker, and some aspects of ERα
function are still unclear. This thesis aims to characterize distinct molecular facets of
ER action relevant for breast cancer and provide valuable information for ER-based
diagnosis and treatment design.
In PAPER I, we analyzed the functionality of two common single
nucleotide polymorphisms in the 3’ untranslated regions of ERβ, rs4986938 and
rs928554, which have been extensively investigated for association with various
diseases. A significant difference in allelic expression was observed for rs4986938 in
breast tumor samples from heterozygous individuals. However, no difference in mRNA
stability or translatability between the alleles was observed.
In PAPER II, we provided a more comprehensive understanding of ERβ
function independent of ERα. A global gene expression analysis in a HEK293/ERβ cell
model identified a set of ERβ-regulated genes. Gene Ontology (GO) analysis showed
that they are involved in cell-cell signaling, morphogenesis and cell proliferation.
Moreover, ERβ expression resulted in a significant decrease in cell proliferation.
In PAPER III, using the human breast cancer MCF-7/ERβ cell model,
we demonstrated, for the first time, the binding of ERα/β heterodimers to various
DNA-binding regions in intact chromatin.
In PAPER IV, we investigated a potential cross-talk between estrogen
signaling and DNA methylation by identifying their common target genes in MCF-7
cells. Gene expression profiling identified around 150 genes regulated by both 17β-
estradiol (E2) and a hypomethylating agent 5-aza-2’-deoxycytidine. Based on GO
analysis, CpG island prediction analysis and previously reported ER binding regions,
we selected six genes for further analysis. We identified BTG3 and FHL2 as direct
target genes of both pathways. However, our data did not support a direct molecular
interplay of mediators of estrogen and epigenetic signaling at promoters of regulated
genes.
In PAPER V, we further explored the interactions between estrogen
signaling and DNA methylation, with focus on DNA methyltransferases (DNMT1,
DNMT3a and DNMT3b). E2, via ERα, up-regulated DNMT1 and down-regulated
DNMT3a and DNMT3b mRNA expression. Furthermore, DNMT3b interacted with
ERα. siRNA-mediated DNMT3b depletion increased the expression of two genes,
CDKN1A and FHL2. We proposed that the molecular mechanism underlying
regulation of FHL2 and CDKN1A gene expression involves interplay of DNMT3b and
ERα.
In conclusion, the studies presented in this thesis contribute to the knowledge of ERβ
function, and give additional insight into the cross-talk mechanisms underlying ERα
signaling with ERβ and with DNA methylation pathways
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