Extent Of Movement Research Articles

Interplay of tactile and motor information in constructing spatial self-perception

During active movement, there is normally a tight relation between motor command and sensory representation about the resulting spatial displacement of the body. Indeed, some theories of space perception emphasize the topographic layout of sensory receptor surfaces, while others emphasize implicit spatial information provided by the intensity of motor command signals. To identify which has the primary role in spatial perception, we developed experiments based on everyday self-touch, in which the right hand strokes the left arm. We used a robot-mediated form of self-touch to decouple the spatial extent of active or passive right hand movements from their tactile consequences. Participants made active movements of the right hand between unpredictable, haptically defined start and stop positions, or the hand was passively moved between the same positions. These movements caused a stroking tactile motion by a brush along the left forearm, with minimal delay, but with an unpredictable spatial gain factor. Participants judged the spatial extent of either the right hand's movement, or of the resulting tactile stimulation to their left forearm. Across five experiments, we found that movement extent strongly interfered with tactile extent perception, and vice versa. Crucially, interference in both directions was stronger during active than passive movements. Thus, voluntary motor commands produced stronger integration of multiple sensorimotor signals underpinning the perception of personal space. Our results prompt a reappraisal of classical theories that reduce space perception to motor command information.

Ankle complex proprioception and plantar cutaneous sensation in older women with different physical activity levels

Ankle complex proprioception and plantar sole sensitivity have been separately reported to be essential sensory components in balance control among the elderly. However, their inter-relationship is still unknown. Further, although optimal proprioceptive ability has been related to regular physical exercise, the association between physical activity (PA) levels, ankle proprioceptive acuity and plantar cutaneous sensation is unclear. Therefore, this study aims to compare ankle proprioceptive acuity and plantar cutaneous sensitivity scores between groups of older women with different PA levels, and to determine any relationships between plantar sole cutaneous sensitivity, ankle proprioceptive performance and PA levels. 68 older female participants were recruited who were distributed over three PA levels: highly active, moderately active, and inactive. PA level was assessed by the International Physical Activity Questionnaire. Ankle proprioceptive acuity was tested in full weight-bearing stance using the ankle Active Movement Extent Discrimination Apparatus (AMEDA) and plantar cutaneous sensitivity was assessed with the Nylon Semmes-Weinstein monofilaments test. Results showed that ankle proprioceptive acuity scores were strongly positively related to plantar sole sensitivity scores (r = 0.80, p < 0.001; effect size: η2 = 0.715), and both scores correlated with PA level. In conclusion, plantar cutaneous sensitivity and ankle complex proprioception were strongly correlated in older females with different levels of physical activity, suggesting that the former may be an integral part of the latter. Given the previously reported contribution of AMEDA ankle proprioceptive acuity to sport performance level, the health of the plantar sole of the foot may be important as a performance determinant.

Could road constructions be more hazardous than an earthquake in terms of mass movement?

Roads can have a significant impact on the frequency of mass wasting events in mountainous areas. However, characterizing the extent and pervasiveness of mass movements over time has rarely been documented due to limitations in available data sources to consistently map such events. We monitored the evolution of a road network and assessed its effect on mass movements for a 11-year window in Arhavi, Turkey. The main road construction projects run in the area are associated with a hydroelectric power plant as well as other road extension works and are clearly associated with the vast majority (90.1%) of mass movements in the area. We also notice that the overall number and size of the mass movements are much larger than in the naturally occurring comparison area. This means that the sediment load originating from the anthropogenically induced mass movements is larger than its counterpart associated with naturally occurring landslides. Notably, this extra sediment load could cause river channel aggregation, reduce accommodation space and as a consequence, it could lead to an increase in the probability and severity of flooding along the river channel. This marks a strong and negative effect of human activities on the natural course of earth surface processes. We also compare frequency-area distributions of human-induced mass movements mapped in this study and co-seismic landslide inventories from the literature. By doing so, we aim to better understand the consequences of human effects on mass movements in a comparative manner. Our findings show that the damage generated by the road construction in terms of sediment loads to river channels is compatible with the possible effect of a theoretical earthquake with a magnitude greater than Mw = 6.0.

Real Estate Investment Trusts and Commercial Property Markets in US

This article addresses the dynamic relationship between the commercial property market and the real estate investment trusts market at the aggregate and property levels by undertaking a co-integration analysis. The results suggest that there exists a common long-run co-integrating relationship between the commercial property and real estate investment trusts markets at the aggregate and property levels. Any disequilibrium in this long-run relationship between these markets is corrected by movement in the real estate investment trusts market. Further, to address the extent of movement in these variables as part of one co-integrated system into permanent and transitory components, we use the Kalman filter by conducting a state-space model. The results show that the cyclical component in the real estate trusts market is large at the aggregate and property levels, which are consistent with co-integrations results.

Zebrafish embryo neonicotinoid developmental neurotoxicity in the FET test and behavioral assays.

The need for reliable, sensitive (developmental) neurotoxicity testing of chemicals has steadily increased. Given the limited capacities for routine testing according to accepted regulatory guidelines, there is potential risk to human health and the environment. Most toxicity studies are based on mammalian test systems, which have been questioned for low sensitivity, limited relevance for humans, and animal welfare considerations. This increased the need for alternative models, one of which is the zebrafish (Danio rerio) embryo. This study assessed selected neonicotinoids at sub-lethal concentrations for their effects on embryonic development and behavior. The fish embryo acute toxicity test (OECD TG 236) determined the lowest observable effective concentrations, which were used as the highest test concentrations in subsequent behavioral assays. In the FET test, no severe compound-induced sublethal effects were seen at < 100 µM. In the coiling assay, exposure to ≥ 1.25 µM nicotine (positive control) affected both the burst duration and burst count per minute, whereas ≥ 50 µM thiacloprid affected the mean burst duration. Exposure to ≥ 50 µM acetamiprid and imidacloprid induced significant alterations in both mean burst duration and burst count per minute. In the swimming assay, 100 µM acetamiprid induced alterations in the frequency and extent of movements, whilst nicotine exposure only induced non-significant changes. All behavioral changes could be correlated to findings in mammalian studies. Given the quest for alternative test methods of (developmental) neurotoxicity, zebrafish embryo behavior testing could be integrated into a future tiered testing scheme.

Quantifying Plasmodesmatal Transport with an Improved GFP Movement Assay.

Plasmodesmata (PD) are membrane-lined channels that cross the cell wall to connect the cytosol of adjacent plant cells, permitting diverse cytosolic molecules to move between cells. PD are essential for plant multicellularity, and the regulation of PD transport contributes to metabolism, developmental patterning, abiotic stress responses, and pathogen defenses, which has sparked broad interest in PD among diverse plant biologists. Here, we present a straightforward method to reproducibly quantify changes in the rate of PD transport in leaves. Individual cells are transformed with Agrobacterium to express fluorescent proteins, which then move beyond the transformed cell via PD. Forty-eight to 72h later, the extent of GFP movement is monitored by confocal fluorescence microscopy. This assay is versatile and may be combined with transient gene overexpression, virus-induced gene silencing, physiological treatments, or pharmaceutical treatments to test how PD transport responds to specific conditions. We expect that this improved method for monitoring PD transport in leaves will be broadly useful for plant biologists working in diverse fields.

Recounting bias can affect abundance estimates from intensive helicopter surveys of feral goats

Context Aerial surveys are widely used for estimating the abundance of wildlife over large areas. The failure to count all animals within survey transects is commonly acknowledged and there are many techniques to measure and correct for underestimation. However, the possibility of animals being counted more than once in intensive surveys, which leads to overestimation, is rarely examined. Animals can move in response to observers or vehicles, and bias can occur when animals move before or after detection. Movement of animals immediately prior to and associated with observation processes is methodologically accommodated in distance sampling but bias attributable to responsive movement after observation platforms have passed requires investigation. Aims We sought to investigate potential biases caused by animal movement during intensive helicopter surveys of feral goats, and to quantify the probability that animals are available for recounting because of their responsive movements. Methods Using ground-based behavioural studies simultaneous with intensive helicopter strip surveys of feral goats, we measured the extent of responsive movement, distances and directions moved, and sampling design parameters, and contrasted those with random movements. Key results Feral goats did not move randomly in response to helicopters. Animals within the transect strips, and therefore potentially visible from the aircraft, were more likely to move than those outside the transect. Considerable responsive movement (flushing) occurred between transects and more animals (64%, n = 448) moved towards unsampled transects than towards transects already sampled. Because of the spatial separation of transects, 21% of goats were available for recounting in adjacent transects, leading to potential overestimation. Conclusions Although most extensive surveys of macropods and other wildlife in Australia account for overestimation in their design, surveys that sample intensively and apply valid corrections for undercounting are likely to produce positively biased estimates of abundance where flushing occurs. Likewise, intensive thermal surveys could be subject to positive bias for animals prone to flushing. This is routinely ignored in wildlife management and research where close transects are used to estimate abundance. Implications Responsive movement requires consideration when designing intensive aerial surveys of wildlife. Randomised transects without replacement or larger distances between transects will counteract recounting bias.

Real-Time MRI Reveals Unique Insight into the Full Kinematics of Eye Movements.

Our eyes are constantly in motion and the various kinds of eye movements are closely linked to many aspects of human cognitive processing. Measuring all possible eye movements unobtrusively is not achievable with current methods. Video-based eye-trackers only measure rotational but not translational motion of the eye, require a calibration process relying on the participant’s self-report of accurate fixation, and do not work if vision of the eyeball is blocked. Scleral search coils attach physical weight on the eyeball and also do not measure translation. Here, we describe a novel and fully automated method to use real-time magnetic resonance imaging (MRI) for eye tracking. We achieved a temporal resolution sufficient to measure eye rotations and translations as short as those that occur within a blink and behind a closed eyelid. To demonstrate this method, we measured the full extent of the blink-related eye movement for two individuals, suggesting that the eye approaches a holding position during lid closure and can move by as much as 35° in rotation and 2 mm in translation. We also investigated the coordination of gaze shifts with blinks. We found that the gaze shift is tightly coupled in time to the translational blink movement and that blinks can induce significant temporal shifts of the gaze trajectory between left and right eye. Our MR-based Eye Tracking (MREyeTrack) method allows measurement of eye movements in terms of both translation and rotation and enables new opportunities for studying ocular motility and its disorders.

Physical Modeling of Snow Gliding: A Case Study in the NW Italian Alps

Snow gliding, a slow movement downhill of snow cover, is complex to forecast and model and yet is extremely important, because it drives snowpack dynamics in the pre-avalanching phase. Despite recent interest in this process and the development of some studies therein, this phenomenon is poorly understood and represents a major point of uncertainty for avalanche forecasting. This study presents a data-driven, physically based, time-dependent 1D model, Poli-Glide, able to predict the slow movement of snowpacks along a flow line at the daily scale. The objective of the work was to create a useful snow gliding model, requiring few, relatively easily available input data, by (i) modeling snowpack evolution from measured precipitation and air temperature, (ii) evaluating the rate and extent of movement of the snowpack in the gliding phase, and (iii) assessing fracture (i.e., avalanching) timing. Such a model could be then used to provide hazard assessment in areas subject to gliding, thereby, and subsequent avalanching. To do so, some simplifying assumptions were introduced, namely that (i) negligible traction stress occurs within soil, (ii) water percolation into snow occurs at a fixed rate, and (iii) the micro topography of soil is schematized according to a sinusoidal function in the absence of soil erosion. The proposed model was then applied to the “Torrent des Marais-Mont de La Saxe” site in Aosta Valley, monitored during the winters of 2010 and 2011, featuring different weather conditions. The results showed an acceptable capacity of the model to reproduce snowpack deformation patterns and the final snowpack’s displacement. Correlation analysis based upon observed glide rates further confirmed dependence against the chosen variables, thus witnessing the goodness of the model. The results could be a valuable starting point for future research aimed at including more complex parameterizations of the different processes that affect gliding.

Developmental Factors That Predict Head Movement During Resting-State Functional Magnetic Resonance Imaging in 3-7-Year-Old Stuttering and Non-stuttering Children.

Early childhood marks a period of dynamic neurocognitive development. Preschool-age coincides with the onset of many childhood disorders and is a developmental period that is frequently studied to determine markers of neurodevelopmental disorders. Magnetic resonance imaging (MRI) is often used to explore typical brain development and the neural bases of neurodevelopmental disorders. However, acquiring high-quality MRI data in young children is challenging. The enclosed space and loud sounds can trigger unease and cause excessive head movement. A better understanding of potential factors that predict successful MRI acquisition would increase chances of collecting useable data in children with and without neurodevelopmental disorders. We investigated whether age, sex, stuttering status, and childhood temperament as measured using the Child Behavioral Questionnaire, could predict movement extent during resting-state functional MRI (rs-fMRI) in 76 children aged 3–7 years, including 42 children who stutter (CWS). We found that age, sex, and temperament factors could predict motion during rs-fMRI scans. The CWS were not found to differ significantly from controls in temperament or head movement during scanning. Sex and age were significant predictors of movement. However, age was no longer a significant predictor when temperament, specifically effortful control, was considered. Controlling for age, boys with higher effortful control scores moved less during rs-fMRI procedures. Additionally, boys who showed higher negative affectivity showed a trend for greater movement. Considering temperament factors in addition to age and sex may help predict the success of acquiring useable rs-fMRI (and likely general brain MRI) data in young children in MR neuroimaging.

Probabilistic Analysis of the Obstruction of Water Sources Due to the Occurrence of Rainfall-Triggered Mass Movements

This paper presents a methodology for the probabilistic estimation of the obstruction of water streams generated by shallow mass movements triggered by rainfall. The study focuses on the Ovejas River, a tributary stream of the Medellín River, in the jurisdiction of the municipality of San Vicente in the department of Antioquia (Colombia). The occurrence of a mass movements was evaluated by deterministic and probabilistic methods based on the automation of processes of Geographic Information Systems (GIS) and spatial modeling. The spatial distribution of the mass movement hazard was estimated in terms of Factor of Safety (FoS) values by the deterministic method with physical basis SLIDE (Slope - Infiltration - Distributed Equilibrium), which allows the hazard zonation by calculating a FoS for rainfall-induced mass movements with different return periods. The rainfall regimes of the study area are estimated by means of a simple scaling Log Normal Model. On the other hand, the Probability of Failure (PF) analysis was performed under Rosenblueth’s punctual estimates method (PEM), which allows incorporating the uncertainty of the soil parameters. Subsequently, the resulting zones with high hazard that could detach and reach the Ovejas River channel are identified as sources for runout modeling by means of the Flow R model, thus estimating the extent of mass movement in probabilistic terms. In all the analyzed scenarios, the sliding material from the critical stability zones has a high probability of spreading to the riverbed of the main river. This analysis makes possible to identify those areas of the riverbed that should be analyzed with more detail and require possible intervention for the protection of the riverbed.

Physical performance and fitness gain during an Infantry Commanders Course are influenced by chronic ankle instability

Introduction: Army training often incurs physical injury, with ankle injuries occurring in 10-20 % of soldiers during training. These patterns are reported with similar frequency and body-part distribution of injury in Israeli Defence Force (IDF) combat units. Research has shown that 32 % of individuals with ankle injuries develop chronic ankle instability (CAI). This study aimed to determine whether having chronic ankle instability (CAI) affects the physical performance of soldiers during their army training, as measured in routine army fitness tests, and in other neuromuscular tests. It was hypothesised that soldiers with CAI would not perform as well on all lower limb performance tests, and would improve less during the period of military training. Methods: A prospective cohort comparison was made within soldiers undertaking the Infantry Commanders Course (IC Course) of the IDF. Soldiers were tested at weeks one and 14 of the course, including with a 3,000m timed run, an agility test over an X-shaped course, the Y Balance Test (YBT) and the Active Movement Extent Discrimination Assessment (AMEDA) somatosensory test. All participants completed the required physical training throughout the course. Changes in physical performance were analysed using a two-way ANOVA, for soldier groups categorised as having healthy ankles or CAI based on a score of ≤25 on the Cumberland Ankle Instability Tool (CAIT) questionnaire. Results: 105 soldiers (mean (±SD) height 1.75m ± 0.06, weight 75.15kg ± 10.74) participated and were separated into those with and without CAI (n=59 and 46, respectively). Overall, scores on all 4 tests (3,000 m run, X-agility test, YBT and AMEDA) improved during the course. However, soldiers with CAI did not improve on the X-agility test, while those with healthy ankles did. At the start of the course, soldiers with CAI performed worse on the YBT-PM (postero-medial direction), but this difference was no longer present at 14 weeks. Compared with their healthy counterparts, soldiers with CAI performed better on the AMEDA at the start and 14 -week testing points. Discussion: Ankle instability restricts agility gains in soldiers during 14-weeks of physical training but has no effect on 3,000m running performance. Soldiers with CAI perform worse in YBT balance tests, in the Anterior and PM directions particularly. Soldiers with CAI have better somatosensory acuity than those with stable ankles, despite the CAI association with worse performance in other tests. This heightened somatosensory awareness may enable them to compensate for lower performance in other tests. Conflict of interest statement: “This study was supported by a research grant from the Medical Research Directorate of the Israeli Defence Forces. No other specific grant funding was received from agencies in the public, commercial, or not-for-profit sectors.”

Ankle Proprioception in Male and Female Surfers and the Implications of Motor Experience and Lower-Body Strength.

Dowse, RA, Secomb, JL, Bruton, M, Parsonage, J, Ferrier, B, Waddington, G, and Nimphius, S. Ankle proprioception in male and female surfers and the implications of motor experience and lower-body strength. J Strength Cond Res 36(12): 3497-3504, 2022-The primary objectives were to evaluate if the active movement extent discrimination apparatus (AMEDA) condition (i.e., front foot and back foot plantarflexion, dorsiflexion, inversion, and eversion) and the level of competition explained ankle movement discrimination scores and, thereafter, examined the contribution of surf experience, physical capacity, and ability to proprioception. It was also considered important to re-evaluate the surf experience, anthropometric characteristics, physical capacities, and abilities of male and female surfers. Twenty-six male ( n = 12, surf experience = 18 ± 8 years) and female surfers ( n = 14, surf experience = 9 ± 6 years) completed a pre-exercise medical questionnaire, anthropometric assessment, 8 AMEDA assessments, countermovement jump, squat jump, and isometric midthigh pull assessment. The AMEDA condition and level of competition did not have a statistically significant main effect on ankle movement discrimination scores; however, the effect of the gender/sex was significant ( p = 0.044). Surf experience ( p = 0.029) and lower-body isometric strength ( p = 0.029) had a statistically significant but small main effect on ankle movement discrimination scores. The results also confirmed that there were significant differences in surf experience, anthropometric characteristics, physical capacity, and jumping ability between male and female surfers. As surf experience and physical capacity were only able to explain a small magnitude of ankle movement discrimination scores, it is suggested that ankle proprioception in surfers may be related to both the volume and quality of the motor experience attained, which may be augmented by environmental and sociocultural factors.

Effect of an anti-adhesion agent on vision-based assessment of cervical adhesions after thyroid surgery: randomized, placebo-controlled trial

Many patients experience cervical adhesions after thyroid surgery. To date, however, no studies have objectively measured the effects of anti-adhesion agents on cervical adhesion symptoms. This study evaluated the effects of an anti-adhesion agent on cervical adhesions after thyroid surgery, as determined using a system that measures the extent of marker movement objectively. One hundred patients were randomized in a 1:1 ratio to undergo thyroid surgery with or without the anti-adhesion agent Collabarrier. Using specially manufactured recording equipment, the position of the marker on neck skin was measured before surgery, and 2 weeks, 3 months, and 9 months after surgery. Relative change in marker distance, calculated by subtracting the marker position before surgery from the marker positions 2 weeks, 3 months, and 9 months after surgery, differed significantly in the groups of patients who underwent thyroid surgery with and without the anti-adhesion agent (P < 0.05). A novel measuring system can objectively evaluate the effectiveness of a thyroid anti-adhesion agent. The anti-adhesion agent used significantly reduced adhesions compared with the control group. The trial is registered at www.cris.nih.go.kr (KCT0005745; date of registration, 08/01/2021).

Parametrizing the genioplasty: a biomechanical virtual study on soft tissue behavior

PurposeSliding genioplasty is used to surgically correct a retruded or misaligned chin: in this procedure, an osteotomy is performed and the bony segment is repositioned. In this study we investigate the effect of surgical parameters (bony segment movement, osteotomy design) on postop soft tissue changes in a patient cohort.MethodsSeven patients were retrospectively recruited. Cone beam computed tomography data were obtained and soft tissue and bone shape reconstructions were performed. 3D models were created and surgical cuts were replicated according to postop scans. Each model was imported in ANSYS 2019R1 (Ansys Inc, USA) for simulation: the effect of variation in osteotomy plane as well as extent of bony segment movement were assessed by means of design of experiment: surgical parameters were varied in a surgically acceptable range and the soft tissue predictions were evaluated as displacement output of five craniometric landmarks.ResultsSimulation results show the overall changes of the lower third of the face are sensitive to changes in horizontal and vertical displacement of the bony segment as well as segment rotation. No significant changes in the soft tissue response were to attribute to the osteotomy design.ConclusionsOur results are consistent with experimental findings reported in the literature: when planning genioplasty in orthognathic surgery, particular focus on the segment movement (horizontal translation, vertical translation and rotation), rather than on the design of the osteotomy itself, should be considered.

Rapid colonisation post‐displacement contributes to native fish resilience

AbstractNative freshwater fish are experiencing global declines. Determining what drives native fish resilience to disturbance is crucial to understanding their persistence in the face of multiple stressors. Fish colonisation ability may be one factor affecting population resilience after disturbance. We conducted displacement experiments in headwater streams in Wyoming, USA, to evaluate mottled sculpin (Cottus bairdii) and mountain sucker (Catostomus platyrhynchus) colonisation ability. Specifically, we (1) determined whether fish could colonise sites rapidly after displacement, (2) evaluated site‐level factors affecting colonisation, and (3) compared species‐level differences in movement and colonisation capabilities. Mountain sucker recovered to pre‐displacement abundances within 6–11 weeks, but mottled sculpin were still at slightly reduced abundances. For both species, the majority of colonists were unmarked new individuals and size–structure was similar to pre‐displacement size–structure. Fish colonisation was best predicted by pre‐displacement abundance and an interaction between per cent riparian cover and species identity. The slower colonisation rate of mottled sculpin may relate to movement ability as average daily movement rate and movement extent were significantly greater for mountain sucker. Our results demonstrate that colonisation is one mechanism allowing fish populations to be resilient in the face of disturbance and that species' traits provide insight into fish colonisation capabilities. Experimental approaches provide mechanistic insight into colonisation dynamics, enhancing our understanding of native fish resilience in degraded stream ecosystems and their response to restoration actions.

Continental-Scale Network Reveals Cross-Jurisdictional Movements of Sympatric Sharks With Implications for Assessment and Management

Understanding the movement ecology of marine species and connectivity of populations is required for effective fisheries management. This is especially the case for species with wide-ranging distributions for which movement can span across several jurisdictions with different management regulations. We used the Australian national network of acoustic receivers facilitated by the Integrated Marine Observing System (IMOS) to describe the extent and frequency of movements for two large epipelagic shark species, the bronze whaler (Carcharhinus brachyurus) and dusky shark (Carcharhinus obscurus). A total of 210 sharks (117 bronze whalers and 93 dusky sharks) were tracked for a 10-year period during which 21% and 9% of detected bronze whalers and dusky sharks, respectively, moved between Australian states. Bronze whalers showed more variable inter-state movements, mostly between Western Australia and South Australia but also eastwards to New South Wales (NSW). Although no dusky sharks tagged in Western Australia undertook inter-state movements, ∼50% of the sharks tagged in South Australia went to Western Australia. Five of the 14 dusky sharks tagged in NSW (36%) were detected across different states but remained on the east and southeast coasts (Queensland, NSW, Victoria, and Tasmania). The IMOS receivers also detected six bronze whalers in Ningaloo Reef, representing an extension of the previously known Australian distribution. Our findings highlight the value of collaboration between researchers and the value of national infrastructure, by providing a more accurate understanding of inter-state movements. This new information will allow the development of more adequate population dynamic models for stock assessment and management advice, requiring collaboration among state agencies for coordinating research activities, sharing data and resources, and establishing appropriate cross-jurisdictional policies. This is essential to achieve successful management and conservation outcomes for highly migratory species.

Movement patterns of temperate wrasses (Labridae) within a small marine protected area.

The movement patterns of three commercially important wrasse (Labridae) species inside a small marine protected area (~ 0.15 km2 ) on the west coast of Norway were analysed over a period of 21 months. The mean distance between capture and recapture locations varied between 10 and 187 m, and was species and season specific. The extent of movement was not related to body size or sex. These results imply that a network of small strategically located marine protected areas can be used as management tools to protect wrasses from size- and sex-selective fishing mortality.

Myeloid HIF1α Is Involved in the Extent of Orthodontically Induced Tooth Movement.

During orthodontic tooth movement, transcription factor hypoxia-inducible factor 1α (HIF1α) is stabilised in the periodontal ligament. While HIF1α in periodontal ligament fibroblasts can be stabilised by mechanical compression, in macrophages pressure application alone is not sufficient to stabilise HIF1α. The present study was conducted to investigate the role of myeloid HIF1α during orthodontic tooth movement. Orthodontic tooth movement was performed in wildtype and Hif1αΔmyel mice lacking HIF1α expression in myeloid cells. Subsequently, µCT images were obtained to determine periodontal bone loss, extent of orthodontic tooth movement and bone density. RNA was isolated from the periodontal ligament of the control side and the orthodontically treated side, and the expression of genes involved in bone remodelling was investigated. The extent of tooth movement was increased in Hif1αΔmyel mice. This may be due to the lower bone density of the Hif1αΔmyel mice. Deletion of myeloid Hif1α was associated with increased expression of Ctsk and Acp5, while both Rankl and its decoy receptor Opg were increased. HIF1α from myeloid cells thus appears to play a regulatory role in orthodontic tooth movement.

SOIL MOVEMENT FOR COMMON CHISEL PLOW SHARES IN EGYPT

Movement of the soil particles during tillage operation is the result of the application of force by the tillage tools. The soil crushed due to the action of the applied force, and soil particles move in various directions. The extent of unnecessary soil movement by tillage tools during tillage practices will affect the rate of soil erosion. Moreover, there is a lack of experimental data concerning soil movement with currently used tillage tools and particularly the effect of repeated tillage over decades of time (Sharifat and Kushwaha, 1997). Under this study, a factorial experiment (2x3x3x3) with random design was used. The tool operating parameters were share shape, plowing speed and constant level of share depth. On the other hand, the soil parameters were soil moisture content and soil compaction. Soil movement was determined using the tracer method introduced by Turkelboom et al. (1996). Results of statistical analysis showed that there are highly significant differences were obtained for the soil movements in three directions with all factors and with the interaction between factors at P£ 0.01. It could be concluded that the use of shovel share instead of sweep share for the same job will reduce soil movement and consequently reduce the rate of soil erosion.