SLA-controlled interconnection charging in next generation networks

Next generation network (NGN) should facilitate a single party to establish quality of service (QoS) enabled path between the two IP providers mutually interconnected by one or more transit providers. For that purpose, an end-to-end service level agreement (SLA) should be negotiated and maintained. In this article, we propose interconnection charging, which is controlled by the end-to-end SLA. Relationships between the required, offered, and actually achieved inter-provider QoS are quantified through the degrees of offering and provisioning, at both end-to-end and per-domain levels. Nominal retail price offered to end users and interconnection costs related with particular SLA are then corrected if needed, depending on the offered and provisioned QoS levels. We further propose five policies for interconnection charging and compare them under different QoS provisioning scenarios. Results of the analysis indicate that a properly selected SLA-controlled interconnection charging policy should encourage providers: (1) to offer services with different QoS levels; (2) to offer service that perfectly or most approximately matches the required QoS and (3) to achieve the contracted QoS level.     

E-Learning personalization based on hybrid recommendation strategy and learning style identification

Personalized learning occurs when e-learning systems make deliberate efforts to design educational experiences that fit the needs, goals, talents, and interests of their learners. Researchers had recently begun to investigate various techniques to help teachers improve e-learning systems. In this paper, we describe a recommendation module of a programming tutoring system - Protus, which can automatically adapt to the interests and knowledge levels of learners. This system recognizes different patterns of learning style and learners’ habits through testing the learning styles of learners and mining their server logs. Firstly, it processes the clusters based on different learning styles. Next, it analyzes the habits and the interests of the learners through mining the frequent sequences by the AprioriAll algorithm. Finally, this system completes personalized recommendation of the learning content according to the ratings of these frequent sequences, provided by the Protus system. Some experiments were carried out with two real groups of learners: the experimental and the control group. Learners of the control group learned in a normal way and did not receive any recommendation or guidance through the course, while the students of the experimental group were required to use the Protus system. The results show suitability of using this recommendation model, in order to suggest online learning activities to learners based on their learning style, knowledge and preferences.     

Denoising of multicomponent images using wavelet least-squares estimators

In this paper, we study denoising of multicomponent images. The presented procedures are spatial wavelet-based denoising techniques, based on Bayesian least-squares optimization procedures, using prior models for the wavelet coefficients that account for the correlations between the spectral bands. We analyze three mixture priors: Gaussian scale mixture models, Bernoulli-Gaussian mixture models and Laplacian mixture models. These three prior models are studied within the same framework of least-squares optimization. The presented procedures are compared to Gaussian prior model and single-band denoising procedures. We analyze the suppression of non-correlated as well as correlated white Gaussian noise on multispectral and hyperspectral remote sensing data and Rician distributed noise on multiple images of within-modality magnetic resonance data. It is shown that a superior denoising performance is obtained when (a) the interband covariances are fully accounted for and (b) prior models are used that better approximate the marginal distributions of the wavelet coefficients.     

Physicochemical and electrochemical properties of the carbon materials containing nitrogen and cobalt derived from acetonitrile and Co–Al layered double hydroxides

Two sets of the carbon materials containing nitrogen and cobalt were prepared by simultaneous carbonization of CH₃CN and decomposition of Co–Al layered double hydroxides (LDHs) (of Co/Al atomic ratios equal to 2 or 3) at 600, 700 and 800 °C followed by treatment with HCl. The physicochemical features of the samples were characterized by means of XRD, TG, EA, XPS, XRF, FT-IR, SEM, Raman spectroscopy and nitrogen sorption. All of the composites were active in oxygen reduction reaction (ORR) in alkaline medium. Their ORR behaviour was determined by the contribution of structural defects and N-doping in graphitic lattice. The beneficial effect of metallic cobalt encapsulated inside the N-CNTs on the ORR performance was also taken into consideration. The studies showed that the likelihood of the existence of Co–N–C species and their participation in ORR seemed to be suppressed by the formation of CoAl₂O₄. The samples prepared at 600 and 700 °C appeared to be more active in ORR than that obtained at 800 °C. The number of electrons involved in ORR (2.89, 2.82 and 2.77) decreased with increasing synthesis temperature for the samples prepared with LDHs of Co/Al?=?2 as a consequence of lowering concentration of nitrogen (3.2, 2.4 and 1.5 wt%), in particular diminishing contribution of pyridinic nitrogen, and decreasing exposure of graphitic edges (I_D1/I_G?~?2.6, 2.0 and 1.0). The ORR performance of the samples prepared with LDHs of Co/Al?=?3 is comparable to that of the corresponding samples prepared with LDHs of Co/Al?=?2.     

Synthesis and Anticancer Activity of Mitotic-Specific 3,4-Dihydropyridine-2(1H)-thiones

Most anticancer drugs target mitosis as the most crucial and fragile period of rapidly dividing cancer cells. However the limitations of classical chemotherapeutics drive the search for new more effective and selective compounds. For this purpose structural modifications of the previously characterized pyridine analogue (S1) were incorporated aiming to obtain an antimitotic inhibitor of satisfactory and specific anticancer activity. Structure-activity relationship analysis of the compounds against a panel of cancer cell lines allowed to select a compound with a thiophene ring at C5 of a 3,4-dihydropyridine-2(1H)-thione (S22) with promising antiproliferative activity (IC₅₀ equal 1.71 ± 0.58 µM) and selectivity (SI = 21.09) against melanoma A375 cells. Moreover, all three of the most active compounds from the antiproliferative study, namely S1, S19 and S22 showed better selectivity against A375 cells than reference drug, suggesting their possible lower toxicity and wider therapeutic index. As further study revealed, selected compounds inhibited tubulin polymerization via colchicine binding site in dose dependent manner, leading to aberrant mitotic spindle formation, cell cycle arrest and apoptosis. Summarizing, the current study showed that among obtained mitotic-specific inhibitors analogue with thiophene ring showed the highest antiproliferative activity and selectivity against cancer cells.     

Carbon Monoxide and Nitric Oxide as Examples of the Youngest Class of Transmitters

The year 2021 is the 100th anniversary of the confirmation of the neurotransmission phenomenon by Otto Loewi. Over the course of the hundred years, about 100 neurotransmitters belonging to many chemical groups have been discovered. In order to celebrate the 100th anniversary of the confirmation of neurotransmitters, we present an overview of the first two endogenous gaseous transmitters i.e., nitric oxide, and carbon monoxide, which are often termed as gasotransmitters.     

Electrodeposition for antibacterial nickel-oxide-based coatings

Nickel-oxide-based films exhibiting antibacterial activity against both Gram-negative (Escherichia coli) and Gram-positive bacteria (Bacillus atrophaeus) have been fabricated by electrodeposition from aqueous solutions. However, after annealing of the films, no antibacterial activity has been observed. As-deposited films were found to consist of a mixture of nickel-oxide hydroxide and nickel hydroxide, while annealing resulted in the conversion of the films into pure NiO. Also, annealed films exhibited no production of H₂O₂, unlike as-deposited films. Thus, antibacterial activity of as-deposited films is related to the presence of nickel-oxide hydroxide/nickel hydroxide which results in the production of reactive oxygen species and antibacterial activity.     

Tocopherols and Tocotrienols—Bioactive Dietary Compounds; What Is Certain,What Is Doubt?

Tocopherols and tocotrienols are natural compounds of plant origin, available in the nature. They are supplied in various amounts in a diet, mainly from vegetable oils, some oilseeds, and nuts. The main forms in the diet are α- and γ-tocopherol, due to the highest content in food products. Nevertheless, α-tocopherol is the main form of vitamin E with the highest tissue concentration. The α- forms of both tocopherols and tocotrienols are considered as the most metabolically active. Currently, research results indicate also a greater antioxidant potential of tocotrienols than tocopherols. Moreover, the biological role of vitamin E metabolites have received increasing interest. The aim of this review is to update the knowledge of tocopherol and tocotrienol bioactivity, with a particular focus on their bioavailability, distribution, and metabolism determinants in humans. Almost one hundred years after the start of research on α-tocopherol, its biological properties are still under investigation. For several decades, researchers’ interest in the biological importance of other forms of vitamin E has also been growing. Some of the functions, for instance the antioxidant functions of α- and γ-tocopherols, have been confirmed in humans, while others, such as the relationship with metabolic disorders, are still under investigation. Some studies, which analyzed the biological role and mechanisms of tocopherols and tocotrienols over the past few years described new and even unexpected cellular and molecular properties that will be the subject of future research.     

International student perspectives on graduate advising relationships.

International graduate students experience a number of unique challenges as they transition through their training programs. Surprisingly, relatively little research has been conducted on perhaps one of the most crucial predictors of international students’ retention and success within their graduate programs: the advising relationship. Using a total of 367 diverse students who responded to a universitywide survey of international students, the authors were able to use quantitative and qualitative analyses to (a) support the adequacy of the Advisory Working Alliance Inventory (L. Z. Schlosser & C. J. Gelso, 2001) for measuring alliance factors in advising relationships for international students; (b) show that some ratings of alliance were lower than a comparison group of U.S. domestic students; (c) determine that alliance ratings had minimal association with grade point average, gender, or college-level area of study, but were substantially associated with advising satisfaction and desire to change advisors; and (d) reveal themes in advising experiences reflecting constructive and destructive advising experiences. The social justice and future implications of the results are consistent with many historical and contemporary emphases in counseling psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)