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This study examines four months of online discourse of 22 Grade 4 students engaged in efforts to advance their understanding of optics. Their work is part of a school-wide knowledge building initiative, the essence of which is giving students collective responsibility for idea improvement. This goal is supported by software-Knowledge Forum-designed to provide a public and collaborative space for continual improvement of ideas. A new analytic tool-inquiry threads-was developed to analyze the discourse used by these students as they worked in this environment. Data analyses focus on four knowledge building principles: idea improvement; real ideas, authentic problems (involving concrete/empirical and abstract/conceptual artifacts); community knowledge (knowledge constructed for the benefit of the community as a whole); and constructive use of authoritative sources. Results indicate that these young students generated theories and explanation-seeking questions, designed experiments to produce real-world empirical data to support their theories, located and introduced expert resources, revised ideas, and responded to problems and ideas that emerged as community knowledge

Tumor immune evasion is a hallmark of cancer. The programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) pathway has been suggested to play an important role in T cell tolerance and tumor immune escape. In this study, we aimed to evaluate the correlation between the expression of PD-1/PD-L1 and the post-treatment outcome in patients with nasopharyngeal carcinoma (NPC). Formalin-fixed, paraffin-embedded tissue biopsies from 139 patients with histological diagnosis of NPC treated with conventional chemoradiotherapy were studied. By using immunohistochemistry staining, expressions of PD-1 on tumor-infiltrating lymphocyte and PD-L1 on tumor tissue were detected. The staining results were evaluated with H-score. The correlation between PD-1/PD-L1 expression and clinical characteristics and post-treatment outcome were analyzed. PD-1(+) immune cell were present in 52 of these 139 tumors (37.4%). PD-L1 expression was detected in 132 patients (95.0%), which located on tumor tissue. High expression of PD-L1 (median H-score >35) in tumor tissue significantly correlated with a poor prognosis of disease-free survival (P = 0.009). Co-expression of PD-1 and PD-L1 in NPC at diagnosis correlated with the poorest prognosis of disease-free survival (P = 0.038). PD-1/PD-L1 co-expression reflected the selective suppression of cytotoxic lymphocytes in the tumor microenvironment and predicted recurrence and metastasis of NPC after conventional therapies. Blocking this pathway in patients with co-expression of PD-1/PD-L1 provides a potential therapy target for NPC.