For learners in distributed e-learning environments, it is difficult, but very important, to locate the right peer for collaboration on the right knowledge, at the right time and in the right way. This paper proposes the use of context awareness (CA) to support peer recommendation in the e-learning context. For this purpose, this paper explores the e-learning context that involves knowledge , social and technical contexts . Accordingly, this paper proposes a threedimensional CA model for peer recommendation that includes CA to knowledge potential , social proximity and technical access . By matching the peer seeker and the peer candidate with respect to these three dimensions, the CA information is promising as an aid to the peer seeker in finding suitable knowledge collaborators. The importance of activity context is highlighted in CAsupported peer-recommendation mechanism. A five-dimensional (who, what, how, when and where) representation approach is suggested for activitycontext description.
Processive hydrolysis of crystalline cellulose by cellulases is a critical step for lignocellulose deconstruction. The classic Trichoderma reesei exoglucanase TrCel7A, which has a closed active-site tunnel, starts each processive run by threading the tunnel with a cellulose chain. Loop regions are necessary for tunnel conformation, resulting in weak thermostability of fungal exoglucanases. However, endoglucanase CcCel9A, from the thermophilic bacterium Clostridium cellulosi, comprises a glycoside hydrolase (GH) family 9 module with an open cleft and five carbohydrate-binding modules (CBMs) and hydrolyzes crystalline cellulose processively. How CcCel9A and other similar GH9 enzymes bind to the smooth surface of crystalline cellulose to achieve processivity is still unknown. Our results demonstrate that the C-terminal CBM3b and three CBMX2s enhance productive adsorption to cellulose, while the CBM3c adjacent to the GH9 is tightly bound to 11 glucosyl units, thereby extending the catalytic cleft to 17 subsites, which facilitates decrystallization by forming a supramodular binding surface. In the open cleft, the strong interaction forces between substrate-binding subsites and glucosyl rings enable cleavage of the hydrogen bonds and extraction of a single cellulose chain. In addition, subsite -4 is capable of drawing the chain to its favored location. Cellotetraose is released from the open cleft as the initial product to achieve high processivity, which is further hydrolyzed to cellotriose, cellobiose and glucose by the catalytic cleft of the endoglucanase. On this basis, we propose a wirewalking mode for processive degradation of crystalline cellulose by an endoglucanase, which provides insights for rational design of industrial cellulases.
Data with categorical attributes are ubiquitous in the real world. However, existing partitional clustering algorithms for categorical data are prone to fall into local optima. To address this issue, in this paper we propose a novel clustering algorithm, ABC-K-Modes (Artificial Bee Colony clustering based on K-Modes), based on the traditional k-modes clustering algorithm and the artificial bee colony approach. In our approach, we first introduce a one-step k-modes procedure, and then integrate this procedure with the artificial bee colony approach to deal with categorical data. In the search process performed by scout bees, we adopt the multi-source search inspired by the idea of batch processing to accelerate the convergence of ABC-K-Modes. The performance of ABC-K-Modes is evaluated by a series of experiments in comparison with that of the other popular algorithms for categorical data.
Expression and clinical value of long non-coding RNA (lncRNA) MALAT1 and lncRNA ANRIL in glaucoma patients were investigated. Altogether 86 glaucoma patients who were diagnosed (study group) and 86 people who underwent physical examinations and were confirmed to be healthy (control group) in the Hospital of Chengdu University of Traditional Chinese Medicine from January 2016 to June 2018 were enrolled. Expression of the serum lncRNA MALAT1, lncRNA ANRIL, pigment epithelium-derived factor (PEDF), homocysteine (Hcy), and inflammatory cytokines [interleukin-12 (IL-12), interleukin-4 (IL-4) and interferon-γ (IFN-γ)] was detected. The clinical significance of lncRNA MALAT1 and lncRNA ANRIL was analyzed. Compared with those in the control group, patients in the study group had significantly lower expression of serum lncRNA MALAT1 and lncRNA ANRIL (P<0.05), significantly lower expression of serum PEDF and IL-12 (P<0.05), and significantly higher expression of serum Hcy and IL-4 (P<0.05), without significant difference in the expression of serum IFN-γ between the two groups (P>0.05). Serum lncRNA MALAT1 and lncRNA ANRIL were positively correlated with PEDF and IL-12 (P<0.05), but negatively correlated with Hcy and IL-4 (P<0.05). The diagnostic value of the combined detection of lncRNA MALAT1 and lncRNA ANRIL was higher than that of lncRNA MALAT1 alone and lncRNA ANRIL alone. The expression of lncRNA MALAT1 and lncRNA ANRIL was significantly related to the pathological staging of the patients (P<0.05), not the sex, age, body mass index (BMI), types, and presence or absence of myopia (P>0.05). lncRNA MALAT1 and lncRNA ANRIL are poorly expressed in the serum of glaucoma patients and related to the patients' conditions. Their combined detection has high diagnostic value for the disease. Therefore, they may be used as new molecular targets for the diagnosis and severity evaluation of glaucoma patients.
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