An examination of constraints affecting the intralimb coordination of hemiparetic gait

A dynamical systems approach to the study of locomotor intralimb coordination in those with hemiparesis led to an examination of the utility of the shank-thigh relative phase (RP) as a collective variable and the identification of potential constraints that may shape this coordination. Eighteen non-disabled individuals formed three groups matched to the age and gender of six participants with chronic right hemiparesis. The three groups differed in the constraints imposed on their walking: (1) walking at their preferred walking speed; (2) walking as slowly as those with hemiparesis; and, (3) walking slowly with a right ankle-foot orthosis (AFO). The results revealed an asymmetry in intralimb coordination between the unaffected and affected leg of those with hemiparesis localized to the latter third of the gait cycle when the limb is advanced from the end of stance to the reestablishment of a new stance. Walking slowly with or without an AFO resulted in no measureable effect in the non-disabled, but accounts for 22% of the variance in the intralimb coordination of the hemiplegic's affected limb and 16% in the unaffected limb. The AFO offered little additional contribution. These results derive from shank-thigh RP that is shown to provide more information about intralimb coordination than knee angle displacement. Implications for these results and the use of RP for rehabilitation are discussed. (C) 2000 Elsevier B.V. B.V. All rights reserved. PsycINFO classification. 3297. 2330.

Spectroscopic study and local coordination of polyphosphate colloidal systems

The interaction between metaphosphate chains and the metal ions Ca2+ and Eu3+ has been studied in water by Eu3+ luminescence, infrared absorption, and P-31 NMR spectroscopy. Two main families of sites could be identified for the metal ions in the aqueous polyphosphate colloidal systems: (1) cagelike sites provided by the polyphosphate chain and (2) a family which arises following saturation of cagelike sites. Occupation of this second family leads to supramolecular interactions between polyphosphate chains and the consequent destabilization of the colloidal system. In the polyphosphate-Ca2+ system, this destabilization appears as a coacervation process. Equilibrium existing between colloidal species as a function of the compositions could be reasoned based on the spectroscopic measurements. The determination of coordination numbers and the correlation of the results with the observation of coacervates show that Eu3+ luminescence properties can be used to probe in a unique way the coacervation process.

Coordination of Eu3+ ions in siliceous nanohybrids containing short polyether chains and bridging urea cross-links

Infrared and photoluminescence spectroscopies have been used to investigate the local environment of the Eu3+ ions in luminescent sol-gel derived materials-di-ureasils-based on a hybrid framework represented by U(600). This host is composed of a siliceous backbone grafted, through urea cross-links, to both ends of polymer segments incorporating 8.5 oxyethylene repeat units. The active centers have been introduced as europium perchlorate, Eu(ClO4)3. Samples with compositions n = 232, 62, 23, 12, and 6 (where n denotes the ratio of (OCH2CH2) moieties per lanthanide ion) have been examined. The combination of the information retrieved from the analysis of characteristic bands of the FTIR spectra-the perchlorate and the Amide I/Amide II features-with that obtained from the photoluminescence data demonstrates that at compositions n = 232 and 62 the anions are free, whereas the Eu3+ ions are complexed by the heteroatoms of the polyether chains. At higher salt concentration, the cations are bonded, not only to the ClO4 - ions, but also to the ether oxygen atoms of the organic segments and to the carbonyl oxygen atoms of the urea linkages. The dual behavior of U(600) with respect to cation coordination has been attributed to the presence in this nanohybrid of strong hydrogen-bonded urea-urea structures, which, at low salt content, cannot be disrupted, thus inhibiting the formation of Eu3+-O=C(urea) contacts and promoting the interaction between the lanthanide ions and the (OCH2CH2) moieties. The present work substantiates the claim that the activation of the coordinating sites of the di-ureasil framework can be tuned by varying either the guest salt concentration at constant chain length or the length of the.organic segments at constant salt concentration. This relevant property opens challenging new prospects in the fields of application of this class of hybrids. © 2001 American Chemical Society.

Interactive system for placement and coordination of overcurrent protective devices

In this paper, an expert and interactive system for developing protection system for overhead and radial distribution feeders is proposed. In this system the protective devices can be allocated through heuristic and an optimized way. In the latter one, the placement problem is modeled as a mixed integer non-linear programming, which is solved by genetic algorithm (GA). Using information stored in a database as well as a knowledge base, the computational system is able to obtain excellent conditions of selectivity and coordination for improving the feeder reliability indices. Tests for assessment of the algorithm efficiency were carried out using a real-life 660-nodes feeder. © 2006 IEEE.

Coordination of spinal motion in the transverse and frontal planes during walking in people with and without recurrent low back pain

STUDY DESIGN. Observational cohort study. OBJECTIVE. To investigate spinal coordination during preferred and fast speed walking in pain-free subjects with and without a history of recurrent low back pain (LBP). SUMMARY OF BACKGROUND DATA. Dynamic motion of the spine during walking is compromised in the presence of back pain (LBP), but its analysis often presents some challenges. The coexistence of significant symptoms may change gait because of pain or adaptation of the musculoskeletal structures or both. A history of LBP without the overlay of a current symptomatic episode allows a better model in which to explore the impact on spinal coordination during walking. METHODS. Spinal and lower limb segmental motions were tracked using electromagnetic sensors. Analyses were conducted to explore the synchrony and spatial coordination of the segments and to compare the control and subjects with LBP. RESULTS. We found no apparent differences between the groups for either overall amplitude of motion or most indicators of coordination in the lumbar region; however, there were significant postural differences in the mid-stance phase and other indicators of less phase locking in controls compared with subjects with LBP. The lower thoracic spinal segment was more affected by the history of back pain than the lumbar segment. CONCLUSION. Although small, there were indicators that alterations in spinal movement and coordination in subjects with recurrent LBP were due to adaptive changes rather than the presence of pain. © 2013, Lippincott Williams & Wilkins.

Coordination of construction behavior in the termite Procornitermes araujoi: structure is a stronger stimulus than volatile marking

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The nucleus of the solitary tract and the coordination of respiratory and sympathetic activities

It is well known that breathing introduces rhythmical oscillations in the heart rate and arterial pressure levels. Sympathetic oscillations coupled to the respiratory activity have been suggested as an important homeostatic mechanism optimizing tissue perfusion and blood gas uptake/delivery. This respiratory-sympathetic coupling is strengthened in conditions of blood gas challenges (hypoxia and hypercapnia) as a result of the synchronized activation of brainstem respiratory and sympathetic neurons, culminating with the emergence of entrained cardiovascular and respiratory reflex responses. Studies have proposed that the ventrolateral region of the medulla oblongata is a major site of synaptic interaction between respiratory and sympathetic neurons. However, other brainstem regions also play a relevant role in the patterning of respiratory and sympathetic motor outputs. Recent findings suggest that the neurons of the nucleus of the solitary tract (NTS), in the dorsal medulla, are essential for the processing and coordination of respiratory and sympathetic responses to hypoxia. The NTS is the first synaptic station of the cardiorespiratory afferent inputs, including peripheral chemoreceptors, baroreceptors and pulmonary stretch receptors. The synaptic profile of the NTS neurons receiving the excitatory drive from afferent inputs is complex and involves distinct neurotransmitters, including glutamate, ATP and acetylcholine. In the present review we discuss the role of the NTS circuitry in coordinating sympathetic and respiratory reflex responses. We also analyze the neuroplasticity of NTS neurons and their contribution for the development of cardiorespiratory dysfunctions, as observed in neurogenic hypertension, obstructive sleep apnea and metabolic disorders.

Synthesis and spectroscopic characterization of a novel coordination polymer of palladium(II) with pyrazole and azido ligands

The one-dimensional coordination polymer of palladium(II) with pyrazolato (Pz -) and azide (N 3 -) as bridging ligands, of formula [Pd 3(μ-N 3)(μ-Pz) 5] n, has been prepared. From IR and Raman studies it was evidenced the exobidentate nature of pyrazole ligands as well the μ-1,1-bridging coordination of azido groups. NMR experiments showed two sets of broadened signals with different intensities indicating the presence of pyrazolato groups in distinct chemical environments. The proposed structure of [Pd 3(μ-N 3)(μ-Pz) 5] n consists of a zigzag ribbon in which each (Pz) 2Pd(Pz) 2 entity is bound to two stacked planar units [Pd(μ-Pz)(μ-N 3)Pd core] with very weak Pd-Pd interaction, based on UV-Vis spectroscopy.

Immunomodulatory Effects of Palladium(II) Complexes of 1,2,4-Triazole on Murine Peritoneal Macrophages

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Synthesis, X-ray structure and antimycobacterial activity of silver complexes with alpha-hydroxycarboxylic acids

In this paper, synthesis, characterization and antimycobacterial properties of a new water-soluble complex identified as silver-mandelate are described. Elemental and thermal analyses are consistent with the formula [Ag(C6H5C(OH)COO)](n). The polymeric structure was determined by single X-ray diffraction and the two-dimensional structure is based on the bis(carboxylate-O,O') dimer [Ag-O, 2.237(3), 2.222(3) angstrom]. The structure is extended along both the b and c axes through two oxygen atoms of a bidentate alpha-hydroxyl-carboxylate residue [Ag-OH(hydroxyl), 2.477(3) angstrom; Ag-O(carboxylate), 2.502(3) angstrom; O-Ag-O, 63.94(9)degrees]. A strong d(10)-d(10) interaction was observed between two silver atoms. The Ag...Ag distance is 2.8307(15) angstrom. The NMR C-13 spectrum in D2O shows that coordination of the ligand to Ag(l) occurs through the carboxylate group in solution. Potentiometric titration shows that only species with a molar metaHigand ratio of 2:2 are formed in aqueous solution. The mandelate complex and the silver-glycolate, silver-malate and silver-hydrogen-tartarate complexes were tested against three types of mycobacteria, Mycobacterium avium, Mycobacterium tuberculosis and Mycobacterium kansasii, and their minimal inhibitory concentration (MIC) values were determined. The results show that the four complexes are potential candidates for antiseptic or disinfectant drugs for discharged secretions of patients affected with tuberculosis. (c) 2006 Published by Elsevier B.V.

Repeated unrewarded scent exposure influences the food choice of stingless bee foragers, Melipona scutellaris

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Mitosis and cell death in the optic lobes of workers, queens and drones of the honey bee (Apis mellifera) during metamorphosis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Activation of Ca2+-independent membrane-damaging activity in Lys49-phospholipase A(2) promoted by amphiphilic molecules

Association of class-II phospholipase A(2) (PLA(2)) with aggregated phospholipid substrate results in elevated levels of the Ca2+-dependent hydrolytic activity. The Asp49 residue participates in coordination of the Ca2+ ion cofactor, however, in Lys49-PLA(2) homologues (Lys49-PLA(2)S), substitution of the Asp49 by Lys results in loss of Ca2+ binding and lack of detectable phospholipid hydrolysis. Nevertheless, Lys49-PLA2S cause Ca2+-independent damage of liposome membranes. Bothropstoxin-I is a homodimeric Lys49-PLA(2) from the venom of Bothrops jararacussu, and in fluorescent marker release and dynamic light scattering experiments with DPPC liposomes we demonstrate activation of the Ca2+-independent membrane damaging activity by similar to4 molecules of sodium dodecyl sulphate (SDS) per protein monomer. Activation is accomparlied by significant changes in the intrinsic tryptophan fluorescence emission (ITFE) and near UV circular dichroism (UVCD) spectra of the protein. Subsequent binding of 7-10 SDS molecules results in further alterations in the ITFE and far UVCD spectra. Reduction in the rate of N-bromosuccinimide modification of Trp77 at the dimer interface suggests that initial binding of SDS to this region accompanies the activation of the membrane damaging activity. 1-anilinonaphthalene-8-sulphonic acid binding studies indicate that subsequent SDS binding to the active site is concomitant with the second structural transition. These results provide insights in the structural basis of amphiphile/protein coupling in class-II PLA(2)s. (C) 2004 Published by Elsevier B.V.

New phosphinate ligand synthesis and its effect on optical properties of the europium beta-diketonate complex

The synthesis and characterization of a new organic ligand monooctyldiphenylphosphinate (L) is described, as well as a new Eu(3+) diketonate complex [Eu(tta)(3)(L)(2)] (tta = thenoyltrifluoracetone). The ligand (L) was formed by substitution reaction (80% yield) and characterized by uni- and bidimensional (1)H, (13)C and (31)P NMR experiments, to confirm its molecular structure. The coordination of (L) to Eu(3+) in the complex [Eu(tta)(3)(L)(2)] was confirmed by FT-IR spectra. The emission spectra present the same profile when excited in Eu(3+) or in the ligands, suggesting an energy transfer from ligands to Eu(3+) ions. The emission spectra of the precursor [Eu(tta)(3)(H(2)O)(2)], and [Eu(tta)(3)(L(2))] present bands arising from f-f intra-configurational transitions. The only (5)D(0)-(7)F(0) transition shows the presence of at least one site without symmetry center. The FWHM of such transition is 7 cm(-1) and 57 cm(-1) for [Eu(tta)(3)(H(2)O)(2)] and [Eu(tta)(3)(L)(2)] complexes, respectively. This widening is provided by the presence of large groups around Eu(3+) ion. The calculated intensity parameters Omega(2) and Omega(4) show that the interaction features between center-ion and ligand are different; the small value of Omega(4) is related to long range effects of alkyl chain. The Langmuir isotherms of this ligand and complex have been investigated although their hydrolysis in water subphase does not allow stable monolayers. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Synthesis and characterization of a new platinum(II) complex with L-mimosine

Synthesis and characterization of a new Pt(II)-mimosine complex are described. Elemental, mass spectrometry and thermal analyses for the complex are consistent with the formula [PtCl2(C8H10N2O4)]center dot 1.5H(2)O. C-13 NMR, N-15 NMR and infrared spectroscopy indicate coordination of the ligand to Pt(II) through the N and O atoms in a square-planar geometry. The final residue after thermal treatment was identified as metallic Pt. The complex is soluble in dimethylsulfoxide.