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In this paper, we study the shift on the space of uniformly bounded continuous functions band-limited in a given compact interval with the standard topology of tempered distributions. We give a constructive proof of the existence of minimal subsystems with any given mean dimension strictly less than twice its band-width. A version of real-valued function spaces is considered as well. [ABSTRACT FROM AUTHOR]

In this paper, it is shown that for d ∈ ℕ, a minimal system (X, T) is a d-step pro-nilsystem if its enveloping semigroup is a d-step top-nilpotent group, answering an open question by Donoso. Thus, combining the previous result of Donoso, it turns out that a minimal system (X, T) is a d-step pro-nilsystem if and only if its enveloping semigroup is a d-step top-nilpotent group. [ABSTRACT FROM AUTHOR]

Composite insulators operate in harsh field environments all year round. Their various properties and states of aging require attention. It is important to study the performance changes of composite insulator sheds after aging to evaluate the life of insulators operating on grids. For this reason, 22 composite insulator sheds from different factories, with different voltage levels and different ages years were selected to conduct mechanical properties testing. The mechanical properties include hardness, tensile strength, and elongation at break, and were investigated by thermogravimetric (TGA) testing, surface morphology, and nuclear magnetic resonance (NMR) characterization. The changes in mechanical properties of high temperature vulcanization (HTV) composite insulator silicone rubber aged in the natural environment were analyzed, including the reasons for these changes. The results showed that the transverse relaxation time T2 of the sample was closely related to its aging state. The more serious the silicone rubber's aging, the smaller was the T2. The state of the composite insulator can be evaluated by using T2 and aging years simultaneously. With the actual degree of aging in the silicone rubber intensified, its tensile strength and elongation at break generally showed a downward trend. [ABSTRACT FROM AUTHOR]

In this paper, it is shown that if a dynamical system is null and distal, then it is equicontinuous. It turns out that a null system with closed proximal relation is mean equicontinuous. As a direct application, it follows that a null dynamical system with dense minimal points is also mean equicontinuous. Meanwhile, a distal system with trivial $\text{Ind}_{\text{fip}}$ -pairs and a non-trivial regionally proximal relation of order $\infty$ are constructed. [ABSTRACT FROM AUTHOR]

In this note, it is shown that several results concerning mean equicontinuity proved before for minimal systems are actually held for general topological dynamical systems. Particularly, it turns out that a dynamical system is mean equicontinuous if and only if it is equicontinuous in the mean if and only if it is Banach (or Weyl) mean equicontinuous if and only if its regionally proximal relation is equal to the Banach proximal relation. Meanwhile, a relation is introduced such that the smallest closed invariant equivalence relation containing this relation induces the maximal mean equicontinuous factor for any system. [ABSTRACT FROM AUTHOR]

Background: In the present study, we investigated the possible tumor suppressive effect of microRNA-107 (miR-107) in human breast cancer. Methods: Gene expression of miR-107 in breast cancer cell lines and clinical breast tissues was evaluated by a quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). MiR-107 was stably overexpressed in MCF-7 and MDA-MB-231 cells via lentiviral transduction. Its role in regulating in vitro cancer proliferation, cell cycle, invasion and in vivo tumor growth was evaluated by MTT, flow cytometry, transwell and in vivo tumorigenicity assays, respectively. Association of miR-107 and its downstream target, brain-derived neurotrophic factor (BDNF), was evaluated by luciferase assay and qRT-PCR. BDNF was further upregulated in miR-107-overexpressed MCF-7 and MDA-MB-231 cells to evaluate its role in regulating breast cancer with respect to in vitro proliferation, cell cycle and invasion. Results: MiR-107 was markedly downregulated in both breast cancer cell lines and breast tumors. MiR-107 overexpression was markedly suppressed with respect to in vitro breast cancer proliferation, cell cycle progression and invasion, as well as with respect to in vivo development of breast cancer xenograft. BDNF was found to be the downstream target of miR-107 in breast cancer. BDNF upregulation functionally facilitated in vitro proliferation, cell cycle progression and invasion in miR-107-overexpressed breast cancer cells. Conclusions: MiR-107 is downregulated and has a tumor suppressive effect in breast cancer, likely through regulation via its inverted downstream target of BDNF. [ABSTRACT FROM AUTHOR]

ABSTRACT Recently, Tzung-Her Chen, Wei-Bin Lee, and Hsing-Bai Chen (CLC) proposed a new three-party password-based authenticated key exchange (3PAKE) protocol. This CLC protocol needs not store the security-sensitive table on the server side, which reduces the danger of the server being compromised; also, it has the advantage in terms of the round efficiency and computational cost. However, we find that the leakage of values VA and VB in the CLC protocol will make a man-in-the-middle attack feasible in practice. On the basis of this finding, we present a modified 3PAKE protocol called I-CLC protocol, which is essentially an improved CLC protocol. I-CLC can resist attacks available, including the man-in-the-middle attack that we mentioned on the initial CLC protocol. Meanwhile, the new protocol allows that the participants choose their own passwords by themselves; additionally, the computation cost of I-CLC is lower than that of CLC protocol. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The CLC protocol (proposed by Tzung-Her Chen, Wei-Bin Lee and Hsing-Bai Chen, CLC, for short) is a new three-party password-authenticated key exchange (3PAKE) protocol. This CLC protocol provides a superior round efficiency (only three rounds), and its resources required for computation are relatively few. However, we find that the leakage of values A V and B V in the CLC protocol will make a man-in-the-middle attack feasible in practice, where A V and B V are the authentication information chosen by the server for the participants A and B. In this paper, we describe our attack on the CLC protocol and further present a modified 3PAKE protocol, which is essentially an improved CLC protocol. Our protocol can resist attacks available, including man-in-the-middle attack we mount on the initial CLC protocol. Meanwhile, we allow that the participants choose their own passwords by themselves, thus avoiding the danger that the server is controlled in the initialization phase. Also, the computational cost of our protocol is lower than that of the CLC protocol. [ABSTRACT FROM AUTHOR]