Load and speed effects on the cervical flexion relaxation phenomenon

<p>Abstract</p> <p>Background</p> <p>The flexion relaxation phenomenon (FRP) represents a well-studied neuromuscular response that occurs in the lumbar and cervical spine. However, the cervical spine FRP has not been investigated extensively, and the speed of movement and loading effects remains to be characterized. The objectives of the present study were to evaluate the influence of load and speed on cervical FRP electromyographic (EMG) and kinematic parameters and to assess the measurement of cervical FRP kinematic and EMG parameter repeatability.</p> <p>Methods</p> <p>Eighteen healthy adults (6 women and 12 men), aged 20 to 39 years, participated in this study. They undertook 2 sessions in which they had to perform a standardized cervical flexion/extension movement in 3 phases: complete cervical flexion; the static period in complete cervical flexion; and extension with return to the initial position. Two different rhythm conditions and 3 different loading conditions were applied to assess load and speed effects. Kinematic and EMG data were collected, and dependent variables included angles corresponding to the onset and cessation of myoelectric silence as well as the root mean square (RMS) values of EMG signals. Repeatability was examined in the first session and between the 2 sessions.</p> <p>Results</p> <p>Statistical analyses revealed a significant load effect (P < 0.001). An augmented load led to increased FRP onset and cessation angles. No load × speed interaction effect was detected in the kinematics data. A significant load effect (P < 0.001) was observed on RMS values in all phases of movement, while a significant speed effect (P < 0.001) could be seen only during the extension phase. Load × speed interaction effect was noted in the extension phase, where higher loads and faster rhythm generated significantly greater muscle activation. Intra-session and inter-session repeatability was good for the EMG and kinematic parameters.</p> <p>Conclusions</p> <p>The load increase evoked augmented FRP onset and cessation angles as well as heightened muscle activation. Such increments may reflect the need to enhance spinal stability under loading conditions. The kinematic and EMG parameters showed promising repeatability. Further studies are needed to assess kinematic and EMG differences between healthy subjects and patients with neck pain.</p

Postural control anomalies in children with Tourette syndrome

The goal of the present study was to determine whether postural control is affected in Gilles-de-la-Tourette syndrome (TS). Center of pressure (COP) displacements were recorded in children with TS and unaffected siblings (7-16 yrs) in three conditions using a force platform: 1) Eyes-Open, 2) Eyes-Closed, 3) One-Leg standing with eyes open. The COP range and velocity were higher in children with TS than in unaffected siblings in all conditions. These differences could not be attributed to age, present tic severity, comorbidities (hyperactivity and compulsions) or medication. The data suggest that sub-clinical postural control anomalies are present in TS

Mosquito Infection Responses to Developing Filarial Worms

Human lymphatic filariasis is a mosquito-vectored disease caused by the nematode parasites Wuchereria bancrofti, Brugia malayi and Brugia timori. These are relatively large roundworms that can cause considerable damage in compatible mosquito vectors. In order to assess how mosquitoes respond to infection in compatible mosquito-filarial worm associations, microarray analysis was used to evaluate transcriptome changes in Aedes aegypti at various times during B. malayi development. Changes in transcript abundance in response to the different stages of B. malayi infection were diverse. At the early stages of midgut and thoracic muscle cell penetration, a greater number of genes were repressed compared to those that were induced (20 vs. 8). The non-feeding, intracellular first-stage larvae elicited few differences, with 4 transcripts showing an increased and 9 a decreased abundance relative to controls. Several cecropin transcripts increased in abundance after parasites molted to second-stage larvae. However, the greatest number of transcripts changed in abundance after larvae molted to third-stage larvae and migrated to the head and proboscis (120 induced, 38 repressed), including a large number of putative, immunity-related genes (∼13% of genes with predicted functions). To test whether the innate immune system of mosquitoes was capable of modulating permissiveness to the parasite, we activated the Toll and Imd pathway controlled rel family transcription factors Rel1 and Rel2 (by RNA interference knockdown of the pathway's negative regulators Cactus and Caspar) during the early stages of infection with B. malayi. The activation of either of these immune signaling pathways, or knockdown of the Toll pathway, did not affect B. malayi in Ae. aegypti. The possibility of LF parasites evading mosquito immune responses during successful development is discussed

Long Lamai community ICT4D E‐commerce system modelling: an agent oriented role‐based approach

This paper presents the post‐mortem report upon completion of the Long Lamai e‐commerce development project. Some weaknesses with regards to the current software modelling approach are identified and an alternative role‐based approach is proposed. We argue that the existing software modelling technique is not suitable for modelling, making it difficult to establish a good contract between stakeholders causing delays in the project delivery. The role‐based approach is able to explicitly highlight the responsibilities among stakeholders, while also forming the contract agreement among them leading towards sustainable ICT4D

Long-term fire and forest history of subalpine balsam fir (Abies balsamea) and white spruce (Picea glauca) stands in eastern Canada inferred from soil charcoal analysis

The northernmost balsam fir forest in eastern Canada forms disjunct stands far beyond the extensive balsam fir forest zone of southern Canada. The northern balsam fir stands are distributed in the subalpine belt of high plateaus and coexist locally with white spruce stands. These subalpine stands contrast greatly with black spruce forest stands located in lowlands. Given that subalpine stands are remnants of an earlier northern expansion of the balsam fir forest, the main objective of this study is to assess whether white spruce stands are distinct communities having diverged from the balsam fir forest community earlier in the Holocene or if they rather correspond to a different stage of the chronosequence within the subalpine belt. Macrofossil analysis of charcoal in mineral soils was used to compare the stand-scale fire histories and taxonomic fossil composition of subalpine, old-growth balsam fir stands and white spruce stands. No significant differences of mean number of observed fires (mean = 6.35 fires per site), Holocene fire recurrence at the landscape scale and mean fire-return interval (mean = 580 years) were found between white spruce stands and balsam fir stands. The botanical composition of charcoal fragments from mineral soils showed that Abies, Betula and Picea were present throughout the fire period from 5600 cal. BP to present, and no difference was found in the fossil composition of the balsam fir and white spruce stands. No historical change in the botanical composition of charcoal from soils of both stand types was observed indicating that the initial floristic composition remained through the period of recurrent fires. Charcoal data suggest that white spruce stands are not divergent community types. Rather, the two community types are arranged along a chronosequence of different successional stages within the subalpine relict flora

Effects of manganese on routine semen quality parameters: results from a population-based study in China

<p>Abstract</p> <p>Background</p> <p>Manganese (Mn) is an essential element in humans but its effect on semen quality is unclear. This study therefore aimed to assess the effects of Mn on semen quality in healthy men with no occupational exposure to Mn.</p> <p>Methods</p> <p>Semen samples were obtained from healthy Chinese men 20–59 years old who were recruited from six provinces in China. Individuals with urogenital tract diseases, tuberculosis, or occupational exposure to heavy metals were excluded. A questionnaire survey was conducted, and the external genitalia, semen quality, and serum Mn levels were examined.</p> <p>Results</p> <p>A total of 1,179 volunteers were enrolled in this study. The median serum Mn concentration was 8.2 μg/L (25th percentile (P₂₅)=3.7 μg/L, P₇₅=16.2μg/L). After adjusted area (six provinces), abstinence interval, season, registered residence, age of subjects, education level, income, smoking, and drinking, the risk of teratospermia was increased at serum Mn concentrations >19.40 μg/L (P₈₀) group, with an adjusted odds ratio of 2.27 (95% confidence interval: 1.18–4.37).</p> <p>Conclusion</p> <p>High serum Mn levels appeared to have harmful effects on sperm morphology and motility among healthy men with no occupational exposure to Mn.</p