Highly specific capture and direct MALDI-MS analysis of phosphorylated peptides using novel multifunctional chitosan-GMA-IDA-Fe (III) nanosphere

In this study, we describe a method for highly specific enrichment of phosphopeptides with multifunctional chitosan–glycidyl methacrylate (GMA)–iminodiacetic acid (IDA)–Fe (III) nanospheres for direct analysis by matrix-assisted laser desorption–ionization mass spectrometry (MALDI-MS). This is the first time that chitosan has been used to create nanospheres support material for selective enrichment of phosphopeptides by modification with GMA, derivatization with IDA, and loading with Fe (III) ions. Chitosan-GMA-IDA-Fe (III) nanospheres with a diameter of 20 to 100 nm have multifunctional chemical moieties which confer unique properties, good dispersibility in highly acidic binding buffers, as well as good biocompatibility and chemical stability which improves their specific interaction with phosphopeptides using various types of acid binding buffers. The process of enrichment is very simple, quick, efficient, and specific. Its high specificity and efficiency for purification of phosphopeptides is reflected in the very low and substoichiometric amounts of phosphopeptides which can be detected, in quantities as low as 1:3,000 M ratios. Compared with other state-of the-art technologies such as the use of conventional Fe³⁺-IMAC and TiO₂, these chitosan nanosphere techniques show superior specificity and sensitivity. Moreover, the resultant chitosan-GMA-IDA-Fe³⁺ nanosphere-absorbed phosphopeptides can be either directly analyzed by MALDI-TOF MS analysis or eluted and further analyzed by nano-LC-MS/MS.     

Peakon, loop and solitary travelling wave solutions for the general modified CH-DP equation

Travelling wave solutions for the general modified CH-DP equation u_t − u_xxt + αu²u_x − βu_xu_xx = uu_xxx are developed. By using the dynamical system method, a peakon and a dark soliton are found to coexist for the same wave speed. Exact explicit blow-up solutions are given. By using numerical simulation, a loop solution for a special case is discussed.     

Analytic Hardy spaces on the quantum torus

Analytic Hardy and BMO spaces on the quantum torus are introduced. Some basic properties of these spaces are presented. In particular, the associated H 1-BMO duality theorem is proved. Finally, we discuss some possible extensions of the obtained results.     

关于分数次Marcinkiewicz积分在Hardy空间上的有界性

本文研究了核函数粗糙的分数次Marcinkiewicz积分μΩ,α在Hardy空间上的有界性.利用Hardy空间的原子分解定理,获得了算子μΩ,α的H1,Ln-nα型和(Hp,Lq)型的有界性结果.     

Optimum selection of the dental implant diameter and length in the posterior mandible with poor bone quality – A 3D finite element analysis

This study aimed to evaluate continuous and simultaneous variations of dental implant diameter and length, and to identify their relatively optimal ranges in the posterior mandible under biomechanical consideration. A 3D finite element model of a posterior mandibular segment with dental implant was created. Implant diameter ranged from 3.0 to 5.0 mm, and implant length ranged from 6.0 to 16.0 mm. The results showed that under axial load, the maximum Von Mises stresses in cortical and cancellous bones decreased by 76.53% and 72.93% respectively, with the increasing of implant diameter and length; and under buccolingual load, by 83.97% and 84.93%, respectively. Under both loads, the maximum displacements of implant-abutment complex decreased by 58.09% and 75.53%, respectively. The results indicate that in the posterior mandible, implant diameter plays more significant roles than length in reducing cortical bone stress and enhancing implant stability under both loads. Meanwhile, implant length is more effective than diameter in reducing cancellous bone stress under both loads. Moreover, biomechanically, implant diameter exceeding 4.0 mm and implant length exceeding 12.0 mm is a relatively optimal combination for a screwed implant in the posterior mandible with poor bone quality.     

A hybrid model for selection of an outsourcing provider

Outsourcing is a good strategy for firms that need to reduce operating costs and improve competitiveness and it is important that firms scientifically select appropriate outsourcing providers. Some efforts have been made to find systematic ways to deal with outsourcing problems, but these efforts incorrectly assumed that the criteria used in the decision process are independent, which is not true in the real world. In this study, we propose a new hybrid multiple criteria decision-making (MCDM) model, which addresses the dependent relationships between the various criteria. The relations-structure among the criteria is built with the aid of the decision-making trial and evaluation laboratory (DEMATEL) method. Decision-makers tend to hold diverse opinions about their preferences due to incomplete information and knowledge, or inherent conflict between various departments. We further used the fuzzy preference programming and the analytic network process (ANP) to form a model for the selection of partners for outsourcing providers. The proposed model can help practitioners improve their decision making process, especially when criteria are numerous and inter-related. The method is demonstrated using data from a Taiwanese airline.     

The use of QP-free algorithm in the limit analysis of slope stability

In many mountainous areas, landslides and slope instabilities frequently occur after heavy rainfall and earthquake, and result in enormous casualties and huge economic losses. In order to mitigate the landslides hazard efficiently, a method is required for a better understanding of stability analysis. Fortunately, upper bound theorem of limit analysis provides a practical and effective upper bound approach to evaluate the stability of slopes. And in this approach, the search for the minimum factor of safety can be formulated as a nonlinear constrained optimization. In general, the SQP-type algorithms are used to solve this optimization problem. However, it is quite time consuming and difficult to search the optimum from an arbitrary starting point based on the SQP-type algorithms. Fortunately, a QP-free algorithm based on penalty function and active-set strategy can be globally convergent toward the KKT points with arbitrary starting point, and the rate of convergence is local superlinear or even quadratic. Two classical problems of slope stability are solved by this QP-free algorithm. The results show that the QP-free algorithm would be the better choice than SQP-type algorithms for solving the nonlinear constrained optimization problem which is derived from the upper bound limit analysis of slope stability.     

Model order determination using the Hankel matrix of impulse responses

This letter studies identification problems of model orders using the Hankel matrix of impulse responses of a system and presents two order identification methods: one is based on the singularities or ratios of the Hankel matrix determinants and the other is based on the singular value decomposition of the Hankel matrix. A numerical example verifies the proposed methods.     

Permanence,extinction and periodic solutions in a mathematical model of cell populations affected by periodic radiation

A periodic mathematical model of cell populations affected by periodic radiation is presented and studied in this paper. We obtain some sufficient conditions on the permanence and extinction of the system. Furthermore, criteria on the existence and global asymptotic stability of unique positive periodic solutions are established. Some numerical examples are shown to verify our results. A discussion is presented for further study.     

An alternative class of irreducible polynomials for optimal extension fields

Optimal extension fields (OEF) are a class of finite fields used to achieve efficient field arithmetic, especially required by elliptic curve cryptosystems (ECC). In software environment, OEFs are preferable to other methods in performance and memory requirement. However, the irreducible binomials required by OEFs are quite rare. Sometimes irreducible trinomials are alternative choices when irreducible binomials do not exist. Unfortunately, trinomials require more operations for field multiplication and thereby affect the efficiency of OEF. To solve this problem, we propose a new type of irreducible polynomials that are more abundant and still efficient for field multiplication. The proposed polynomial takes the advantage of polynomial residue arithmetic to achieve high performance for field multiplication which costs O(m ^3/2) operations in \mathbbF_p{\mathbb{F}_p} . Extensive simulation results demonstrate that the proposed polynomials roughly outperform irreducible binomials by 20% in some finite fields of medium prime characteristic. So this work presents an interesting alternative for OEFs.