42 research outputs found
Tensor Decomposition Reveals Concurrent Evolutionary Convergences and Divergences and Correlations with Structural Motifs in Ribosomal RNA
Evolutionary relationships among organisms are commonly described by using a
hierarchy derived from comparisons of ribosomal RNA (rRNA) sequences. We propose that
even on the level of a single rRNA molecule, an organism's evolution is composed
of multiple pathways due to concurrent forces that act independently upon different
rRNA degrees of freedom. Relationships among organisms are then compositions of
coexisting pathway-dependent similarities and dissimilarities, which cannot be
described by a single hierarchy. We computationally test this hypothesis in
comparative analyses of 16S and 23S rRNA sequence alignments by using a tensor
decomposition, i.e., a framework for modeling composite data. Each alignment is
encoded in a cuboid, i.e., a third-order tensor, where nucleotides, positions and
organisms, each represent a degree of freedom. A tensor mode-1 higher-order singular
value decomposition (HOSVD) is formulated such that it separates each cuboid into
combinations of patterns of nucleotide frequency variation across organisms and
positions, i.e., “eigenpositions” and corresponding nucleotide-specific
segments of “eigenorganisms,” respectively, independent of a-priori
knowledge of the taxonomic groups or rRNA structures. We find, in support of our
hypothesis that, first, the significant eigenpositions reveal multiple similarities
and dissimilarities among the taxonomic groups. Second, the corresponding
eigenorganisms identify insertions or deletions of nucleotides exclusively conserved
within the corresponding groups, that map out entire substructures and are enriched
in adenosines, unpaired in the rRNA secondary structure, that participate in tertiary
structure interactions. This demonstrates that structural motifs involved in rRNA
folding and function are evolutionary degrees of freedom. Third, two previously
unknown coexisting subgenic relationships between Microsporidia and Archaea are
revealed in both the 16S and 23S rRNA alignments, a convergence and a divergence,
conferred by insertions and deletions of these motifs, which cannot be described by a
single hierarchy. This shows that mode-1 HOSVD modeling of rRNA alignments might be
used to computationally predict evolutionary mechanisms
Body image disturbance and surgical decision making in egyptian post menopausal breast cancer patients
<p>Abstract</p> <p>Background</p> <p>In most developing countries, as in Egypt; postmenopausal breast cancer cases are offered a radical form of surgery relying on their unawareness of the subsequent body image disturbance. This study aimed at evaluating the effect of breast cancer surgical choice; Breast Conservative Therapy (BCT) versus Modified Radical Mastectomy (MRM); on body image perception among Egyptian postmenopausal cases.</p> <p>Methods</p> <p>One hundred postmenopausal women with breast cancer were divided into 2 groups, one group underwent BCT and the other underwent MRM. Pre- and post-operative assessments of body image distress were done using four scales; Breast Impact of Treatment Scale (BITS), Impact of Event Scale (IES), Situational Discomfort Scale (SDS), and Body Satisfaction Scale (BSS).</p> <p>Results</p> <p>Preoperative assessment showed no statistical significant difference regarding cognitive, affective, behavioral and evaluative components of body image between both studied groups. While in postoperative assessment, women in MRM group showed higher levels of body image distress among cognitive, affective and behavioral aspects.</p> <p>Conclusion</p> <p>Body image is an important factor for postmenopausal women with breast cancer in developing countries where that concept is widely ignored. We should not deprive those cases from their right of less mutilating option of treatment as BCT.</p
Effect of partners’ disgust responses on psychological wellbeing in cancer patients
The aim of this study was to explore quantitatively the relationship between disgust responses in cancer patients and their partners, and in turn their relationship to patients’ psychological well-being. We recruited 50 participants with heterogeneous cancer diagnoses and their partners from cancer-related groups (e.g., charities). Patients completed questionnaires to determine levels of disgust propensity, disgust sensitivity, self-disgust, and symptoms of anxiety and depression. Disgust propensity and sensitivity were also assessed in their partners. Partners’ disgust sensitivity was significantly positively correlated with cancer patients’ self-disgust, disgust propensity, and depression. Path analyses suggested that patients’ self-disgust plays a role in mediating the effect of partners’ disgust sensitivity on patients’ psychological well-being. This study provides the first quantitative evidence that psychological well-being in cancer patients is contingent on their partners’ sensitivity to disgust, and that patients’ self-disgust plays a mediating role. Focusing therapeutically on disgust responses could well be beneficial to people with cancer