Exploiting semantic similarity models to automate transfer credit assessment in academic mobility

Student mobility or academic mobility involves students moving between institutions during their post-secondary education, and one of the challenging tasks in this process is to assess the transfer credits to be offered to the incoming student. In general, this process involves domain experts comparing the learning outcomes (LOs) of the courses, and based on their similarity deciding on offering transfer credits to the incoming students. This manual im- plementation of the task is not only labor-intensive but also influenced by undue bias and administrative complexity. This research work focuses on identifying an algorithm that ex- ploits the advancements in the field of Natural Language Processing (NLP) to effectively automate this process. A survey tracing the evolution of semantic similarity helps under- stand the various methods available to calculate the semantic similarity between text data. The basic units of comparison namely, learning outcomes are made up of two components namely the descriptor part which provides the contents covered, and the action word which provides the competency achieved. Bloom’s taxonomy provides six different levels of com- petency to which the action words fall into. Given the unique structure, domain specificity, and complexity of learning outcomes, a need for designing a tailor-made algorithm arises. The proposed algorithm uses a clustering-inspired methodology based on knowledge-based semantic similarity measures to assess the taxonomic similarity of learning outcomes and a transformer-based semantic similarity model to assess the semantic similarity of the learning outcomes. The cumulative similarity between the learning outcomes is further aggregated to form course to course similarity. Due to the lack of quality benchmark datasets, a new benchmark dataset is built by conducting a survey among domain experts with knowledge in both academia and computer science. The dataset contains 7 course-to-course similarity values annotated by 5 domain experts. Understanding the inherent need for flexibility in the decision-making process the aggregation part of the algorithm offers tunable parame- ters to accommodate different scenarios. Being one of the early research works in the field of automating articulation, this thesis establishes the imminent challenges that need to be addressed in the field namely, the significant decrease in performance by state-of-the-art se- mantic similarity models with an increase in complexity of sentences, lack of large datasets to train/fine-tune existing models, lack of quality in available learning outcomes, and reluc- tance to share learning outcomes publicly. While providing an efficient algorithm to assess the similarity between courses with existing resources, this research work steers future re- search attempts to apply NLP in the field of articulation in an ideal direction by highlighting the persisting research gaps

Active Contour Based Segmentation Techniques for Medical Image Analysis

Image processing is a technique which is used to derive information from the images. Segmentation is a section of image processing for the separation or segregation of information from the required target region of the image. There are different techniques used for segmentation of pixels of interest from the image. Active contour is one of the active models in segmentation techniques, which makes use of the energy constraints and forces in the image for separation of region of interest. Active contour defines a separate boundary or curvature for the regions of target object for segmentation. The contour depends on various constraints based on which they are classified into different types such as gradient vector flow, balloon and geometric models. Active contour models are used in various image processing applications specifically in medical image processing. In medical imaging, active contours are used in segmentation of regions from different medical images such as brain CT images, MRI images of different organs, cardiac images and different images of regions in the human body. Active contours can also be used in motion tracking and stereo tracking. Thus, the active contour segmentation is used for the separation of pixels of interest for different image processing

Requirement of Cognate CD4+ T-Cell Recognition for the Regulation of Allospecific CTL by Human CD4+CD127−CD25+FOXP3+ Cells Generated in MLR

Although immunoregulation of alloreactive human CTLs has been described, the direct influence of CD4+ Tregs on CD8+ cytotoxicity and the interactive mechanisms have not been well clarified. Therefore, human CD4+CD127−CD25+FOXP3+ Tregs were generated in MLR, immunoselected and their allospecific regulatory functions and associated mechanisms were then tested using modified 51Chromium release assays (Micro-CML), MLRs and CFSE-based multi-fluorochrome flow cytometry proliferation assays. It was observed that increased numbers of CD4+CD127−CD25+FOXP3+ cells were generated after a 7 day MLR. After immunoselection for CD4+CD127−CD25+ cells, they were designated as MLR-Tregs. When added as third component modulators, MLR-Tregs inhibited the alloreactive proliferation of autologous PBMC in a concentration dependent manner. The inhibition was quasi-antigen specific, in that the inhibition was non-specific at higher MLR-Treg modulator doses, but non-specificity disappeared with lower numbers at which specific inhibition was still significant. When tested in micro-CML assays CTL inhibition occurred with PBMC and purified CD8+ responders. However, antigen specificity of CTL inhibition was observed only with unpurified PBMC responders and not with purified CD8+ responders or even with CD8+ responders plus Non-T “APC”. However, allospecificity of CTL regulation was restored when autologous purified CD4+ T cells were added to the CD8+ responders. Proliferation of CD8+ cells was suppressed by MLR-Tregs in the presence or absence of IL-2. Inhibition by MLR-Tregs was mediated through down-regulation of intracellular perforin, granzyme B and membrane-bound CD25 molecules on the responding CD8+ cells. Therefore, it was concluded that human CD4+CD127−CD25+FOXP3+ MLR-Tregs down-regulate alloreactive cytotoxic responses. Regulatory allospecificity, however, requires the presence of cognate responding CD4+ T cells. CD8+ CTL regulatory mechanisms include impaired proliferation, reduced expression of cytolytic molecules and CD25+ activation epitopes

Prognosis Following Surgery for Recurrent Ovarian Cancer and Diagnostic Criteria Predictive of Cytoreduction Success: A Systematic Review and Meta-Analysis

For women achieving clinical remission after the completion of initial treatment for epithelial ovarian cancer, 80% with advanced-stage disease will develop recurrence. However, the standard treatment of women with recurrent platinum-sensitive diseases remains poorly defined. Secondary (SCS), tertiary (TCS) or quaternary (QCS) cytoreduction surgery for recurrence has been suggested to be associated with increased overall survival (OS). We searched five databases for studies reporting death rate, OS, cytoreduction rates, post-operative morbidity/mortality and diagnostic models predicting complete cytoreduction in a platinum-sensitive disease recurrence setting. Death rates calculated from raw data were pooled based on a random-effects model. Meta-regression/linear regression was performed to explore the role of complete or optimal cytoreduction as a moderator. Pooled death rates were 45%, 51%, 66% for SCS, TCS and QCS, respectively. Median OS for optimal cytoreduction ranged from 16–91, 24–99 and 39–135 months for SCS, TCS and QCS, respectively. Every 10% increase in complete cytoreduction rates at SCS corresponds to a 7% increase in median OS. Complete cytoreduction rates ranged from 9–100%, 35–90% and 33–100% for SCS, TCS and QCS, respectively. Major post-operative thirty-day morbidity was reported to range from 0–47%, 13–33% and 15–29% for SCS, TCS and QCS, respectively. Thirty-day post-operative mortality was 0–6%, 0–3% and 0–2% for SCS, TCS and QCS, respectively. There were two externally validated diagnostic models predicting complete cytoreduction at SCS, but none for TCS and QCS. In conclusion, our data confirm that maximal effort higher order cytoreductive surgery resulting in complete cytoreduction can improve survival

Population Study of Ovarian Cancer Risk Prediction for Targeted Screening and Prevention

Unselected population-based personalised ovarian cancer (OC) risk assessment combining genetic/epidemiology/hormonal data has not previously been undertaken. We aimed to perform a feasibility study of OC risk stratification of general population women using a personalised OC risk tool followed by risk management. Volunteers were recruited through London primary care networks. Inclusion criteria: women ≥18 years. Exclusion criteria: prior ovarian/tubal/peritoneal cancer, previous genetic testing for OC genes. Participants accessed an online/web-based decision aid along with optional telephone helpline use. Consenting individuals completed risk assessment and underwent genetic testing (BRCA1/BRCA2/RAD51C/RAD51D/BRIP1, OC susceptibility single-nucleotide polymorphisms). A validated OC risk prediction algorithm provided a personalised OC risk estimate using genetic/lifestyle/hormonal OC risk factors. Population genetic testing (PGT)/OC risk stratification uptake/acceptability, satisfaction, decision aid/telephone helpline use, psychological health and quality of life were assessed using validated/customised questionnaires over six months. Linear-mixed models/contrast tests analysed impact on study outcomes. Main outcomes: feasibility/acceptability, uptake, decision aid/telephone helpline use, satisfaction/regret, and impact on psychological health/quality of life. In total, 123 volunteers (mean age = 48.5 (SD = 15.4) years) used the decision aid, 105 (85%) consented. None fulfilled NHS genetic testing clinical criteria. OC risk stratification revealed 1/103 at ≥10% (high), 0/103 at ≥5%−10% (intermediate), and 100/103 at 5% (low) lifetime OC risk. Decision aid satisfaction was 92.2%. The telephone helpline use rate was 13% and the questionnaire response rate at six months was 75%. Contrast tests indicated that overall depression (p = 0.30), anxiety (p = 0.10), quality-of-life (p = 0.99), and distress (p = 0.25) levels did not jointly change, while OC worry (p = 0.021) and general cancer risk perception (p = 0.015) decreased over six months. In total, 85.5−98.7% were satisfied with their decision. Findings suggest population-based personalised OC risk stratification is feasible and acceptable, has high satisfaction, reduces cancer worry/risk perception, and does not negatively impact psychological health/quality of life

Surgical decision making in premenopausal BRCA carriers considering risk-reducing early salpingectomy or salpingo-oophorectomy: a qualitative study.

BACKGROUND: Acceptance of the role of the fallopian tube in 'ovarian' carcinogenesis and the detrimental sequelae of surgical menopause in premenopausal women following risk-reducing salpingo-oophorectomy (RRSO) has resulted in risk-reducing early-salpingectomy with delayed oophorectomy (RRESDO) being proposed as an attractive alternative risk-reducing strategy in women who decline/delay oophorectomy. We present the results of a qualitative study evaluating the decision-making process among BRCA carriers considering prophylactic surgeries (RRSO/RRESDO) as part of the multicentre PROTECTOR trial (ISRCTN:25173360). METHODS: In-depth semistructured 1:1 interviews conducted using a predeveloped topic-guide (development informed by literature review and expert consultation) until informational saturation reached. Wording and sequencing of questions were left open with probes used to elicit additional information. All interviews were audio-recorded, transcribed verbatim, transcripts analysed using an inductive theoretical framework and data managed using NVIVO-v12. RESULTS: Informational saturation was reached following 24 interviews. Seven interconnected themes integral to surgical decision making were identified: fertility/menopause/cancer risk reduction/surgical choices/surgical complications/sequence of ovarian-and-breast prophylactic surgeries/support/satisfaction. Women for whom maximising ovarian cancer risk reduction was relatively more important than early menopause/quality-of-life preferred RRSO, whereas those more concerned about detrimental impact of menopause chose RRESDO. Women managed in specialist familial cancer clinic settings compared with non-specialist settings felt they received better quality care, improved hormone replacement therapy access and were more satisfied. CONCLUSION: Multiple contextual factors (medical, physical, psychological, social) influence timing of risk-reducing surgeries. RRESDO offers women delaying/declining premenopausal oophorectomy, particularly those concerned about menopausal effects, a degree of ovarian cancer risk reduction while avoiding early menopause. Care of high-risk women should be centralised to centres with specialist familial gynaecological cancer risk management services to provide a better-quality, streamlined, holistic multidisciplinary approach