A model for information retrieval driven by conceptual spaces

A retrieval model describes the transformation of a query into a set of documents. The question is: what drives this transformation? For semantic information retrieval type of models this transformation is driven by the content and structure of the semantic models. In this case, Knowledge Organization Systems (KOSs) are the semantic models that encode the meaning employed for monolingual and cross-language retrieval. The focus of this research is the relationship between these meanings’ representations and their role and potential in augmenting existing retrieval models effectiveness. The proposed approach is unique in explicitly interpreting a semantic reference as a pointer to a concept in the semantic model that activates all its linked neighboring concepts. It is in fact the formalization of the information retrieval model and the integration of knowledge resources from the Linguistic Linked Open Data cloud that is distinctive from other approaches. The preprocessing of the semantic model using Formal Concept Analysis enables the extraction of conceptual spaces (formal contexts)that are based on sub-graphs from the original structure of the semantic model. The types of conceptual spaces built in this case are limited by the KOSs structural relations relevant to retrieval: exact match, broader, narrower, and related. They capture the definitional and relational aspects of the concepts in the semantic model. Also, each formal context is assigned an operational role in the flow of processes of the retrieval system enabling a clear path towards the implementations of monolingual and cross-lingual systems. By following this model’s theoretical description in constructing a retrieval system, evaluation results have shown statistically significant results in both monolingual and bilingual settings when no methods for query expansion were used. The test suite was run on the Cross-Language Evaluation Forum Domain Specific 2004-2006 collection with additional extensions to match the specifics of this model

Natural killer (NK) cells and their involvement in different types of cancer. Current status of clinical research

Natural killer cells are the main agents of innate immunity. Since 1970, various studies have repeatedly confirmed their involvement in decreasing local tumor growth and also decreasing the risk of metastasis, due to their cytotoxic effects and also through the release of immunostimulatory cytokines such as IFN-gamma. In the 1990s, several studies demonstrated the existence of certain inhibiting and stimulating receptors of these cells, leading to the concept of “induced self”, thus explaining why tumors with MHC-1 are destroyed and autologous cells without it are saved out. Recognition and destruction of tumor cells by the NK cells are the result of complex interactions between inhibiting and activating factors. This paper, based on extensive research of currently available studies, summarizes the mechanisms employed by the NK cells to destroy the cancer cells, thus highlighting their role in the risk of tumor recurrence as well as their use and handling in certain types of immunotherapy

Rezultatele tratamentului pacienţilor cu insuficienţă renală acută

Summary. A study was performed in the department of Hemodialysis and Renal Transplant of Republican Clinical Hospital, Chişinău to analyse the ethiopathogenesis, different protocols of treatment and complications in the patients with ARF. The study was performed by extensively analysing the data of 417 patients, 260 males (61,77%) and 157 females (38,23%), who were admitted in the RCH over a period of 21 years (from 1979 to 2002). After the study it was found that the incidence of ARF the most common etiology was found to be polyetiologic shock (16,79%), exogenic intoxication (15,35%) and obstetric and gynecologic complications (12,23%). Mortality rate was found to be 22.2 %. Out of 417 patients with ARF, 10 patients progressed to CRF. 307 (73,62%) patients, out of the 417 were treated successfully

A novel biphasic scaffold supports meniscal tissue repair in ex vivo and in vivo models

The objectives of this study were i) to investigate whether a novel biphasic collagen scaffold supports meniscal repair in an ovine meniscal defect model in vivo, ii) to investigate meniscal cell ingrowth and ECM production in an ex-vivo model and iii) to investigate the effect platelet rich plasma (PRP) on the response of meniscal elements to the scaffold.A novel biphasic scaffold (collagen sponge with 300 mm open pores, reinforced with bands of 150 mm internal strengthening fibres) was implanted into a circular defect in the meniscus of adult sheep with and without PRP. Healing in vivo was monitored by longitudinal gait analysis. At 2 and 26 weeks post surgery durometry, histology and immunohistochemistry was performed on recovered menisci. In vitro, ex vivo ovine meniscus/scaffold models were constructed and the effects of PRP on cell migration and extracellular matrix production monitored by cell tracking, protein extraction and Western blotting.In this study we have demonstrated that a novel biphasic collagen scaffold can support meniscal defect repair in an in vivo model and support the ingrowth of meniscal fibrochondrocyte (MFC) in an ex vivo model. In addition we have demonstrated that the addition of PRP significantly enhances MFC migration and ECM production in vitro and promotes rapid defect healing in vivo.This novel biphasic scaffold supports meniscal healing, which is increased in the presence of PRP, likely due to increased MFC migration