Sample Entropy as a Tool to Assess Lumbo-Pelvic Movements in a Clinical Test for Low-Back-Pain Patients

Low back pain (LBP) obviously reduces the quality of life but is also the world’s leading cause of years lived with disability. Alterations in motor response and changes in movement patterns are expected in LBP patients when compared to healthy people. Such changes in dynamics may be assessed by the nonlinear analysis of kinematical time series recorded from one patient’s motion. Since sample entropy (SampEn) has emerged as a relevant index measuring the complexity of a given time series, we propose the development of a clinical test based on SampEn of a time series recorded by a wearable inertial measurement unit for repeated bending and returns (b and r) of the trunk. Twenty-three healthy participants were asked to perform, in random order, 50 repetitions of this movement by touching a stool and another 50 repetitions by touching a box on the floor. The angular amplitude of the b and r movement and the sample entropy of the three components of the angular velocity and acceleration were computed. We showed that the repetitive b and r “touch the stool” test could indeed be the basis of a clinical test for the evaluation of low-back-pain patients, with an optimal duration of 70 s, acceptable in daily clinical practice.     

Spectral multipliers on a class of NA groups with rank two

We consider a family of real NA groups with rank two, and we prove that these groups have sub-Laplacians with differentiable Lp functional calculus for all p?1.     

From isocyanides to trichloropyruvamides: application to a new preparation of oxamide derivatives

Isocyanides react readily with trichloroacetic acid anhydride forming stable hydrates of trichloropyruvamides. These compounds are valuable intermediates for obtaining oxamides by reaction with TMSCl/NEt₃ followed by addition of an amine.     

Use of parallel synthesis to probe structure-activity relationships among 12-helical beta-peptides: evidence of a limit on antimicrobial activity

We report structure-activity trends among helix-forming beta-amino acid oligomers that are intended to mimic alpha-helical host-defense peptides. Parallel synthesis of two small, focused beta-peptide libraries allowed us to identify relatively short (11-residue) beta-peptides that display antimicrobial activity. These beta-peptides exhibit selectivity for bacteria relative to human red blood cells. A large hydrophobic helical surface is necessary for antimicrobial activity. Longer analogues (16 residues) of the most active library members were prepared and evaluated. Some of these longer beta-peptides showed very good antimicrobial activity, but none was more active than a previously reported beta-peptide [Porter, E. A.; Wang, X.; Lee, H.-S.; Weisblum, B.; Gellman, S. H. Nature 2000, 404, 565]. The extensive literature on alpha-helical host-defense peptides and related alpha-peptides indicates that such molecules are seldom active at concentrations below 1 microg/mL, and our results suggest that amphiphilic helical beta-peptides are subject to a comparable limit.     

Concise synthesis of pochonin A, an HSP90 inhibitor

[chemical reaction: see text]. An expedient synthesis of (-)-pochonin A is reported (seven steps). This natural product is closely related to radicicol and was shown to be a 90 nM inhibitor of HSP90.     

Intramolecular cycloaddition of carbonyl ylides generated from α-diazo ketones

Two cases of intramolecular cycloaddition of carbonyl ylides, formed from the α-diazo-ketones1 and8, to a C=C bond within the molecule are described. The structures of the products4a and10 have been established from chemical and spectroscopic evidence and by single crystal X-ray crystallographic analysis of6a and10.     

Electrospray mass spectrometry of lanthanide β-diketone complexes. II-Ligand-exchange processes involving acetate ions and Ln(tfc)3 complexes

Electrospray ionization on Ln(tfc)₃ complexes (Ln = Eu, Yb; tfc = D -3-trifluoroacetylcamphorate) was performed with samples dissolved in methanol–water containing acetic acid. The spectra were obtained with a four-sector mass spectrometer. The mass spectra exhibit ions containing tfc ligand in addition to ions with acetato ligand. Electro-spray and tandem mass spectra are presented.     

Rapid measurements of 235U fission product isotope ratios using an online,high-pressure ion chromatography inductively coupled plasma mass spectrometry protocol with comparison to isotopic depletion models

Journal of Radioanalytical and Nuclear Chemistry - An automated online separation–direct analysis method, RAPID (rapid analysis of post-irradiation debris), has been developed for the...