Enhanced physiological tremor deteriorates plantar flexor torque steadiness after bed rest

This study evaluated the effectiveness of resistance training to preserve submaximal plantar flexor (PF) torque steadiness following 60 days of bed rest (BR). Twenty-two healthy male subjects underwent either BR only (CTR, n=8), or BR plus resistance training (RT, n=14). The magnitude of torque fluctuations during steady submaximal isometric PF contractions (20%, 40%, 60% and 80% of maximum) were assessed before and after BR. Across contraction intensities, torque fluctuations (coefficient of variation, CV) increased more (P<0.05) after BR for CTR (from 0.31±0.10 to 0.92±0.63; P<0.001), than for RT (from 0.30±0.09 to 0.54±0.27; P<0.01). A shift in the spectral content of torque fluctuations towards increased rhythmic activity between 6.5 and 20Hz was observed in CTR only (P<0.05). H-reflex amplitude (H(max)/M(max) ratio) declined across groups from 0.57±0.18 before BR to 0.44±0.14 following BR (P<0.01) without correlation to CV. The present study showed that increased torque fluctuation after BR resulted from enhanced physiological tremor. Resistance training prevented the spectral shift in isometric PF torque fluctuation and offset ∼50% of the decline in performance associated with long-term BR.

A comparative study of rhodopsin function in the great bowerbird (Ptilonorhynchus nuchalis): spectral tuning and light-activated kinetics

Rhodopsin is the visual pigment responsible for initiating the phototransduction cascade in vertebrate rod photoreceptors. Although well-characterized in a few model systems, comparative studies of rhodopsin function, particularly for non-mammalian vertebrates are comparatively lacking. Bowerbirds are rare among passerines in possessing a key substitution, D83N, at a site that is otherwise highly conserved among G protein-coupled receptors. While this substitution is present in some dim-light adapted vertebrates, often accompanying another unusual substitution, A292S, its functional relevance in birds is uncertain. To investigate functional effects associated with these two substitutions, we use the rhodopsin gene from the great bowerbird (Ptilonorhynchus nuchalis) as a background for site-directed mutagenesis, in vitro expression and functional characterization. We also mutated these sites in two additional rhodopsins that do not naturally possess N83, chicken and bovine, for comparison. Both sites were found to contribute to spectral blue-shifts, but had opposing effects on kinetic rates. Substitutions at site 83 were found to primarily affect the kinetics of light-activated rhodopsin, while substitutions at site 292 had a larger impact on spectral tuning. The contribution of substitutions at site 83 to spectral tuning in particular depended on genetic background, but overall, the effects of substitutions were otherwise surprisingly additive, and the magnitudes of functional shifts were roughly similar across all three genetic backgrounds. By employing a comparative approach with multiple species, our study provides new insight into the joint impact of sites 83 and 292 on rhodopsin structure-function as well as their evolutionary significance for dim-light vision across vertebrates.

Acetylacetonato chelated ruthenium organometallics incorporating imine-phenol function: spectroscopic, structural, electrochemical and cytotoxicity studies

The heterogeneous phase reaction of Ru(η²-RL)(PPh₃)₂(CO)Cl, 1 with lithium acetylacetonate (Liacac) afforded the complexes of the type Ru(η¹-RL)(PPh₃)₂(CO)(acac), 2 in excellent yield where η²-RL is C₆H₂O-2-CHNHC₆H₄R(p)-3-Me-5 and η¹-RL is C₆H₂OH-2-CHNC₆H₄R(p)-3-Me-5 and R is H, Me, Cl. The chelation of acac is attended with the cleavage of Ru-O and Ru-Cl bonds and iminium-phenolato → imine-phenol prototropic shift. A sterically controlled change in rotational conformation is involved in the 1 → 2 conversion. The conversion is irreversible and the type 2 species are thermodynamically more stable than the carboxylate, nitrite and nitrate complexes of 1. The crystal structures of Ru(η¹-MeL)(PPh₃)₂(CO)(acac), 2(Me) and Ru(η¹-ClL)(PPh₃)₂(CO)(acac), 2(Cl) are reported. Spectral (UV-Vis, IR, ¹H NMR) and electrochemical data of the complexes are also reported. The electronic structure and the absorption spectra of the complexes are scrutinized by the density functional theory (DFT) and time-dependent density functional theory (TD-DFT) analyses. The complexes were also screened in vitro for their antiproliferative properties against the MCF-7 breast cancer cell lines by using the MTT assay. Flow cytometric analysis showed that the complexes arrested the cell cycle in the sub G0 phase.

Discourses of anxiety in nursing practice : a psychoanalytic case study of the change-of-shift handover ritual

This paper reports on the findings of a study that considered how anxiety might function to organise nurses' practice. With reference to psychoanalytic theory this paper analyses field notes taken during a series of nursing change-of-shift handovers. The handover practices analysed met all the criteria for a ritual, as understood in psychoanalytic theory, and functioned to alleviate anxiety in the short term while symbolically expressing a forbidden and unknown knowledge. We argue that the handover ritual contained certain prohibitions, yet allowed some expression of the prohibited knowledge in a disguised way. The prohibition concerned how the patient affected the nurse, that is, moved the nurse to love and hate the patient. We argue that this prohibition is expressed, in disguise, via the displacement of affection for the patient onto other nurses and through negative stereotyping of some patients. We also argue that these prohibitions of the handover mirror broader prohibitions within nursing, and thus the rituals of the handover become an expression of how professional prohibitions are enacted in practice. We conclude that the important implicit function of the handover ritual is to keep anxiety at bay, thereby enabling the nurse to commence practice rather than being immobilised by the effect of potentially overwhelming anxiety.

On the stress function-based OWA determination method with optimization criteria

The ordered weighted averaging (OWA) determination method with stress function was proposed by Yager, and it makes the OWA operator elements scatter in the shape of the stress function. In this paper, we extend the OWA determination with the stress function method using an optimization model. The proposed method transforms the OWA optimal solution elements into the interpolation points of the stress function. The proposed method extends the basic form of the stress function method with both scale and vertical shift transformations.We also explore a number of properties of this optimization-based stress function method. The OWA operator optimal solution elements can distribute as the shape of the given stress function in a parameterized way, in which case, the solution always possesses the arithmetic average operator as a special case.

Spectral element model updating for damage identification using clonal selection algorithm

A spectral element model updating procedure is presented to identify damage in a structure using Guided wave propagation results. Two damage spectral elements (DSE1 and DSE2) are developed to model the local (cracks in reinforcement bar) and global (debonding between reinforcement bar and concrete) damage in one-dimensional homogeneous and composite waveguide, respectively. Transfer matrix method is adopted to assemble the stiffness matrix of multiple spectral elements. In order to solve the inverse problem, clonal selection algorithm is used for the optimization calculations. Two displacement-based functions and two frequency-based functions are used as objective functions in this study. Numerical simulations of wave propagation in a bare steel bar and in a reinforcement bar without and with various assumed damage scenarios are carried out. Numerically simulated data are then used to identify local and global damage of the steel rebar and the concrete-steel interface using the proposed method. Results show that local damage is easy to be identified by using any considered objective function with the proposed method while only using the wavelet energy-based objective function gives reliable identification of global damage. The method is then extended to identify multiple damages in a structure. To further verify the proposed method, experiments of wave propagation in a rectangular steel bar before and after damage are conducted. The proposed method is used to update the structural model for damage identification. The results demonstrate the capability of the proposed method in identifying cracks in steel bars based on measured wave propagation data.

Effects of task lighting on visual function in age-related macular degeneration

The purpose was to investigate the effects of the spectral power distribution (SPD) and illuminance of task lighting on visual function in age-related macular degeneration (ARMD) compared to normal healthy eyes. Twenty-eight subjects with ARMD and 18 age-matched normal subjects were studied. The effects on visual function were determined for four common task light sources: standard pearl coat incandescent (SP), daylight blue incandescent (DL), warm white fluorescent (WW) and cool white fluorescent (CW). Apart from a small, statistically significant improvement in contrast sensitivity with DL compared to SP lighting (0.5 dB, p = 0.01), there were no significant effects of SPD on other visual functions and no differences in the effects for subjects with ARMD and those with normal vision. Thus, for task lighting typically used in low vision rehabilitation, the SPD would seem to be of minimal clinical importance to visual function. However, increasing the task illuminance had a greater effect on visual function, in particular for subjects with ARMD (p < 0.01). For an increase in illuminance from 300 to 3000 lux, the mean increase in contrast sensitivity and near visual acuity was 1.5 dB and 0.13 log MAR, respectively. Although this effect is not large, we suggest that it is clinically relevant and supports the provision of additional task illuminance as an important part of low vision rehabilitation for patients with ARMD.

Influence of prolonged bed-rest on spectral and temporal electromyographic motor control characteristics of the superficial lumbo-pelvic musculature

Little is known about the motor control of the lumbo-pelvic musculature in microgravity and its simulation (bed-rest). Analysis of spectral and temporal electromyographic variables can provide information on motor control relevant for normal function. This study examined the effect of 56-days of bed-rest with 1-year follow-up in 10 male subjects on the median frequency and the activation timing in surface electromyographic recordings from five superficial lumbo-pelvic muscles during a repetitive knee movement task. Trunk fat mass (from whole body-composition measurements) and movement accuracy as possible explanatory factors were included. Increased median frequency was observed in the lumbar erector spinae starting late in bed-rest, but this was not seen in its synergist, the thoracic erector spinae (p<.0001). These changes persisted up to 1-year after bed-rest and were independent of changes in body-composition or movement accuracy. Analysis suggested decreases of median frequency (p<.0001) in the abdominal and gluteal muscles to result from increased (p<.01) trunk fat levels during and after bed-rest. No changes in lumbo-pelvic muscle activation timing were seen. The results suggest that bed-rest particularly affects the shorter lumbar erector spinae and that the temporal sequencing of superficial lumbo-pelvic muscle activation is relatively robust.

Antisubjectivism and the (spectral) return of consciousness in landscape research

This paper analyses the changing conceptions of consciousness within landscape research over a critical period from the late 20th century to the present. The 1980s and 1990s mark a radical shift in the framing of consciousness away from psychological, perceptual, or experiential perspectives towards an ontology of consciousness as signifier, cultural artifact, and ideology. In cultural geography and the visual arts, these reframings can be characterised as anti subjectivist in that they do not attempt to problematize human consciousness so much as deactivate it and disqualify it from discussion. I draw out the theoretical and critical foundations of these antisubjectivist approaches as well as the subsequent opening out of the notion of landscape in more recent discussion. This ‘opening out’ implicates a more complex reengagement with minds, bodies, and landscapes and with the contested distinctions between subject and object. At the same time however, consciousness is seldom formulated explicitly within the literature and hence consciousness often occupies a spectral presence in the landscape of landscape research. I use one of my own paintings, Dalek in Landscape, to presage the discussion and attempt to highlight the tensions between these ideological, cultural and biological dimensions of consciousness at play within the landscape idea. Given the broader adoption of these anti-subjectivist developments within the academy, the example of landscape serves as a potentially useful case study for thinking upon the changing conceptions of consciousness in cognate creative and academic disciplines.