Pseudotetrahedral cobaltate(II) anions with two and three different kinds of ligands

New complexes of the general types HCo(NCS)₃ ·nL, HCoX ₂(NCS) ·nL and HCo(NCS)₂I ·nL (whereX=Cl, Br, I;L=diethyl ether, pyridine, aniline;n=1.5, 2, 3, 3.5) have been prepared and characterized. The magnetic and spectroscopic data indicate that pseudotetrahedral [Co(NCS)₃ L]^?, [CoX ₂(NCS)L]^? and [Co(NCS)₂IL]^? anions are present in the solid pyridine and aniline compounds.     

Extension Principles for Dual Multiwavelet Frames of $$L_2(\mathbb {R}^s)$$ constructed from Multirefinable Generators

In this work we prove that any pair of homogeneous dual multiwavelet frames of \(L_2(\mathbb {R}^s)\) constructed from a pair of refinable function vectors gives rise to a pair of nonhomogeneous dual multiwavelet frames and vice versa. We also prove that the Mixed Oblique Extension Principle characterizes dual multiwavelet frames. Our results extend recent characterizations of affine dual frames derived from scalar refinable functions obtained in [3].     

Multipurpose organically modified carbon nanotubes: from functionalization to nanotube composites

We show that covalent functionalization of carbon nanotubes (CNTs) via 1,3-dipolar cycloaddition is a powerful method for enhancing the ability to process CNTs and facilitating the preparation of hybrid composites, which is achieved solely by mixing. CNTs were functionalized with phenol groups, providing stable dispersions in a range of polar solvents, including water. Additionally, the functionalized CNTs could easily be combined with polymers and layered aluminosilicate clay minerals to give homogeneous, coherent, transparent CNT thin films and gels.     

Hypersurfaces and Codazzi tensors

In this paper we deal with the following problem. Let (M ⁿ ,〈,〉) be an n-dimensional Riemannian manifold and an isometric immersion. Find all Riemannian metrics on M ⁿ that can be realized isometrically as immersed hypersurfaces in the Euclidean space . More precisely, given another Riemannian metric on M ⁿ , find necessary and sufficient conditions such that the Riemannian manifold admits an isometric immersion into the Euclidean space . If such an isometric immersion exists, how can one describe in terms of f? Author’s address: Thomas Hasanis and Theodoros Vlachos, Department of Mathematics, University of Ioannina, 45110 Ioannina, Greece     

In vivo evaluation and in vitro metabolism of leuprolide in mice--mass spectrometry-based biomarker measurement for efficacy and toxicity

The study of pharmacologically active peptides is central for the understanding of cancer and the development of novel therapeutic approaches. In this context, both qualitative and quantitative determination of bioactive peptides in biological fluids/tissues and their effect on endogenous factors (e.g. hormones) are of great importance. A mass spectrometry-based approach was developed and applied towards the measurement of leuprolide, a peptide drug for the treatment of prostate cancer, in mouse plasma. High-pressure liquid chromatography coupled to a hybrid quadrupole linear ion trap (QqLIT) mass spectrometer, a platform that combines the benefits of triple QqLIT instruments, was employed for the study. Using the described methodology, we established that picomolar concentrations of leuprolide could be measured in mouse plasma (limit of quantification of 0.1 ng/ml). In order to optimize pharmacokinetic properties of analogs of leuprolide, a facile in vivo mouse model was developed and leuprolide concentrations were determined in mouse plasma following intraperitoneal administration. In the same animal model, we demonstrated the versatility of the described MS-based approach by the determination of plasma concentrations of testosterone, an established biomarker for the treatment of prostate cancer. Following dosing with leuprolide, circulating testosterone was increased significantly in comparison to vehicle-treated mice. Finally, in vitro metabolism of leuprolide was evaluated by incubation of leuprolide with mouse kidney membranes, followed by identification of major metabolites by MS. Such studies provide the framework for future evaluation of novel leuprolide analogs with potential therapeutic advantages.     

A characterization of the Clifford torus

We provide a characterization of the Clifford torus via a Ricci type condition among minimal surfaces in S⁴. More precisely, we prove that a compact minimal surface in S⁴, with induced metric ds² and Gaussian curvature K, for which the metric is flat away from points where K = 1, is the Clifford torus, provided that m is an integer with m > 2.Received: 8 September 2004     

Complete Minimal Hypersurfaces in a Sphere

In this paper we investigate complete minimal hypersurfaces with at most two principal curvatures. We prove that if the squared norm S of the second fundamental form satisfies S ≥ n, then S = n and f(Mⁿ) is a minimal Clifford torus.     

Multi-RAT Aggregation Through Spectrum Reallocation for Future Wireless Networks

Wireless Personal Communications - Next generation wireless networks are becoming the main focus of the industry by putting efforts to launch beyond 4G (i.e. 5G) communication systems by 2020....     

A Low-Complexity PTS-based PAPR Reduction Technique for OFDM Signals without Transmission of Side Information

Increased peak-to-average power ratio (PAPR) imposes a design challenge for orthogonal frequency division multiplexing-based signals. An efficient technique to address the increased PAPR problem is the partial transmit sequences (PTS) approach. A significant drawback of PTS is the fact that it multiplies the transmitted symbol with weighting factors selected by the transmitter. Since the weighting factors are required for decoding, they are explicitly transmitted, in most cases. This paper proposes a new low-complexity technique for retrieving the weighting factors in the receiver. The proposed decoder uses the predefined values of pilot tones and explores all the permissible combinations of weighting factors in order to identify the factor combination employed by the transmitter. The proposed decoder requires no additional pilot tones or explicit transmission of side information, therefore no data rate loss is implied. Furthermore this paper presents a digital very large scale integration implementation of the proposed PTS decoder and demonstrates its low-power properties.