The distinctive weathering crust habitat of a High Arctic glacier comprises discrete microbial micro-habitats.

Sunlight penetrates the ice surfaces of glaciers and ice sheets, forming a water-bearing porous ice matrix known as the weathering crust. This crust is home to a significant microbial community. Despite the potential implications of microbial processes in the weathering crust for glacial melting, biogeochemical cycles, and downstream ecosystems, there have been few explorations of its microbial communities. In our study, we used 16S rRNA gene sequencing and shotgun metagenomics of a Svalbard glacier surface catchment to characterise the microbial communities within the weathering crust, their origins and destinies, and the functional potential of the weathering crust metagenome. Our findings reveal that the bacterial community in the weathering crust is distinct from those in upstream and downstream habitats. However, it comprises two separate micro-habitats, each with different taxa and functional categories. The interstitial porewater is dominated by Polaromonas, influenced by the transfer of snowmelt, and exported via meltwater channels. In contrast, the ice matrix is dominated by Hymenobacter, and its metagenome exhibits a diverse range of functional adaptations. Given that the global weathering crust area and the subsequent release of microbes from it are strongly responsive to climate projections for the rest of the century, our results underscore the pressing need to integrate the microbiome of the weathering crust with other communities and processes in glacial ecosystems.

A microbial ecosystem beneath the West Antarctic ice sheet.

Liquid water has been known to occur beneath the Antarctic ice sheet for more than 40 years, but only recently have these subglacial aqueous environments been recognized as microbial ecosystems that may influence biogeochemical transformations on a global scale. Here we present the first geomicrobiological description of water and surficial sediments obtained from direct sampling of a subglacial Antarctic lake. Subglacial Lake Whillans (SLW) lies beneath approximately 800 m of ice on the lower portion of the Whillans Ice Stream (WIS) in West Antarctica and is part of an extensive and evolving subglacial drainage network. The water column of SLW contained metabolically active microorganisms and was derived primarily from glacial ice melt with solute sources from lithogenic weathering and a minor seawater component. Heterotrophic and autotrophic production data together with small subunit ribosomal RNA gene sequencing and biogeochemical data indicate that SLW is a chemosynthetically driven ecosystem inhabited by a diverse assemblage of bacteria and archaea. Our results confirm that aquatic environments beneath the Antarctic ice sheet support viable microbial ecosystems, corroborating previous reports suggesting that they contain globally relevant pools of carbon and microbes that can mobilize elements from the lithosphere and influence Southern Ocean geochemical and biological systems.

Relationships Between Highly Skilled Golfers' Clubhead Velocity and Vertical Ground Reaction Force Asymmetry During Vertical Jumps and an Isometric Midthigh Pull.

Wells, JET, Mitchell, ACS, Charalambous, LH, and Fletcher, IM. Relationships between highly skilled golfers' clubhead velocity and vertical ground reaction force asymmetry during vertical jumps and an isometric midthigh pull. J Strength Cond Res 34(10): 2824-2831, 2020-Clubhead velocity (CHV) is a commonly measured variable within golf due to strong associations with increased drive distance. Previous research has revealed significant relationships between CHV and vertical ground reaction force (vGRF) variables during bilateral tasks including a countermovement jump (CMJ), squat jump (SJ), drop jump (DJ), and isometric midthigh pull (IMTP). Asymmetries have been linked to performance outcomes in a number of sports; however, few studies have assessed asymmetries within golf. The current study, therefore, examined the relationships between CHV and vGRF asymmetries for CMJ positive impulse, SJ positive impulse, DJ positive impulse, and IMTP peak force (PF). Furthermore, the level of agreement for asymmetries between protocols was assessed by using Kappa coefficients. Fifty highly skilled (handicap ≤5) male golfers attended laboratory and range-based testing sessions. Positive impulse and PF were measured using a dual force platform system, with CHV measured using a TrackMan 3e launch monitor. There was no significant relationship (r = -0.14 to 0.22) between CHV and each of the vGRF asymmetry measures. Of the golfers tested, 26 had a "real" asymmetry in the CMJ, 18 had a "real" asymmetry in the SJ, 25 had a "real" asymmetry in the DJ, and 27 had a "real" asymmetry in the IMTP. Kappa coefficients indicated that asymmetries rarely favored the same limb (k = 0.06 to 0.39) with asymmetries varying for individual golfers between protocols. As such, asymmetries are neither beneficial nor detrimental to CHV but are inherently individual and dependent on the task.

Effects of Interrupting Sitting with Use of a Treadmill Desk Versus Prolonged Sitting on Postural Stability.

High amounts of sitting increase the risk of non-communicable disease and mortality. Treadmill desks make it possible to reduce sitting during the desk-based worker's day. This study investigated the acute effect on postural stability of interrupting prolonged sitting with an accumulated 2-h of light-intensity treadmill desk walking. Twenty-one sedentary adults participated in this randomized acute crossover trial, with two 6.5 h conditions: 1) uninterrupted sitting and 2) interrupted sitting with accumulated 2 h light-intensity treadmill desk walking. Pre- and post-condition, participants performed four postural stability tests on a pressure plate (bipedal and unipedal standing stance, eyes open and eyes closed). Anteroposterior center of pressure amplitude showed a significant condition x time interaction in bipedal eyes closed (F(1,20)=4.62, p=0.046) and unipedal eyes open (F(1,20)=9.42, p=0.006) tests, and mediolateral center of pressure amplitude in bipedal eyes closed (F(1,20)=6.12, p=0.023) and bipedal eyes open (F(1,12)=5.55, p=0.029) tests. In the significant interactions, amplitude increased pre to post condition in the uninterrupted sitting condition. The accumulated 2 h light-intensity treadmill desk walking ameliorated the negative effect of 6.5 h prolonged sitting on postural sway, supporting workplace treadmill desk use.

Relationships between Challenge Tour golfers' clubhead velocity and force producing capabilities during a countermovement jump and isometric mid-thigh pull.

A number of field-based investigations have evidenced practically significant relationships between clubhead velocity (CHV), vertical jump performance and maximum strength. Unfortunately, whilst these investigations provide a great deal of external validity, they are unable to ascertain vertical ground reaction force (vGRF) variables that may relate to golfers' CHVs. This investigation aimed to assess if the variance in European Challenge Tour golfers' CHVs could be predicted by countermovement jump (CMJ) positive impulse (PI), isometric mid-thigh pull (IMTP) peak force (PF) and rate of force development (RFD) from 0-50 ms, 0-100 ms, 0-150 ms and 0-200 ms. Thirty-one elite level European Challenge Tour golfers performed a CMJ and IMTP on dual force plates at a tournament venue, with CHV measured on a driving range. Hierarchical multiple regression results indicated that the variance in CHV was significantly predicted by all four models (model one R2 = 0.379; model two R2 = 0.392, model three R2 = 0.422, model four R2 = 0.480), with Akaike's information criterion indicating that model one was the best fit. Individual standardised beta coefficients revealed that CMJ PI was the only significant variable, accounting for 37.9% of the variance in European Challenge Tour Golfers' CHVs.

Relationships between highly skilled golfers' clubhead velocity and force producing capabilities during vertical jumps and an isometric mid-thigh pull.

Whilst previous research has highlighted significant relationships between golfers' clubhead velocity (CHV) and their vertical jump height and maximum strength, these field-based protocols were unable to measure the actual vertical ground reaction force (vGRF) variables that may correlate to performance. The aim of this study was to investigate relationships between isometric mid-thigh pull (IMTP), countermovement jump (CMJ), squat jump (SJ) and drop jump (DJ) vGRF variables and CHV in highly skilled golfers. Twenty-seven male category 1 golfers performed IMTP, CMJ, SJ and DJ on a dual force platform. The vertical jumps were used to measure positive impulse during different stretch-shortening cycle velocities, with the IMTP assessing peak force (PF) and rate of force development (RFD). Clubhead velocity was measured using a TrackMan launch monitor at a golf driving range. Pearsons correlation coefficient analyses revealed significant relationships between peak CHV and CMJ positive impulse (r = 0.788, p < 0.001), SJ positive impulse (r = 0.692; p < 0.001), DJ positive impulse (r = 0.561, p < 0.01), PF (r = 0.482, p < 0.01), RFD from 0-150 ms (r = 0.343, p < 0.05) and RFD from 0-200 ms (r = 0.398, p < 0.05). The findings from this investigation indicate strong relationships between vertical ground reaction force variables and clubhead velocity.

The effect of dimple error on the horizontal launch angle and side spin of the golf ball during putting.

This study aimed to examine the effect of the impact point on the golf ball on the horizontal launch angle and side spin during putting with a mechanical putting arm and human participants. Putts of 3.2 m were completed with a mechanical putting arm (four putter-ball combinations, total of 160 trials) and human participants (two putter-ball combinations, total of 337 trials). The centre of the dimple pattern (centroid) was located and the following variables were measured: distance and angle of the impact point from the centroid and surface area of the impact zone. Multiple regression analysis was conducted to identify whether impact variables had significant associations with ball roll variables, horizontal launch angle and side spin. Significant associations were identified between impact variables and horizontal launch angle with the mechanical putting arm but this was not replicated with human participants. The variability caused by "dimple error" was minimal with the mechanical putting arm and not evident with human participants. Differences between the mechanical putting arm and human participants may be due to the way impulse is imparted on the ball. Therefore it is concluded that variability of impact point on the golf ball has a minimal effect on putting performance.

Accelerometery and Heart Rate Responses of Professional Fast-Medium Bowlers in One-Day and Multi-Day Cricket.

The physical demands of fast-medium bowling are increasingly being recognised, yet comparative exploration of the differing demands between competitive formats (i.e. one-day [OD] versus multi-day [MD] matches) remain minimal. The aim of this study was to describe in-match physiological profiles of professional fast-medium bowlers from England across different versions of competitive matches using a multivariable wearable monitoring device. Seven professional cricket fast-medium bowlers wore the BioharnessTM monitoring device during matches, over three seasons (>80 hours in-match). Heart Rate (HR) and Acceleromety (ACC) was compared across match types (OD, MD) and different in-match activity states (Bowling, Between over bowling, Fielding). Peak acceleration during OD bowling was significantly higher in comparison to MD cricket ([OD vs. MD] 234.1 ± 57.9 vs 226.6 ± 32.9 ct·episode-1, p < 0.05, ES = 0.11-0.30). Data for ACC were also higher during OD than MD fielding activities (p < 0.01, ES = 0.11-.30). OD bowling stimulated higher mean HR responses (143 ± 14 vs 137 ± 16 beats·min-1, p < 0.05, ES = 0.21) when compared to MD matches. This increase in OD cricket was evident for both between over (129 ± 9 vs 120 ± 13 beats·min-1,p < 0.01, ES = 0.11-0.50) and during fielding (115 ± 12 vs 106 ± 12 beats·min-1, p < 0.01, ES = 0.36) activity. The increased HR and ACC evident in OD matches suggest greater acute physical loads than MD formats. Therefore, use of wearable technology and the findings provided give a valuable appreciation of the differences in match loads, and thus required physiological preparation and recovery in fast-medium bowlers.

Reliability of an experimental method to analyse the impact point on a golf ball during putting.

This study aimed to examine the reliability of an experimental method identifying the location of the impact point on a golf ball during putting. Forty trials were completed using a mechanical putting robot set to reproduce a putt of 3.2 m, with four different putter-ball combinations. After locating the centre of the dimple pattern (centroid) the following variables were tested; distance of the impact point from the centroid, angle of the impact point from the centroid and distance of the impact point from the centroid derived from the X, Y coordinates. Good to excellent reliability was demonstrated in all impact variables reflected in very strong relative (ICC = 0.98-1.00) and absolute reliability (SEM% = 0.9-4.3%). The highest SEM% observed was 7% for the angle of the impact point from the centroid. In conclusion, the experimental method was shown to be reliable at locating the centroid location of a golf ball, therefore allowing for the identification of the point of impact with the putter head and is suitable for use in subsequent studies.

The athletic profile of fast bowling in cricket: a review.

Cricket is a global sport played in over 100 countries with elite performers attracting multimillion dollar contracts. Therefore, performers maintaining optimum physical fitness and remaining injury free is important. Fast bowlers have a vital position in a cricket team, and there is an increasing body of scientific literature that has reviewed this role over the past decade. Previous research on fast bowlers has tended to focus on biomechanical analysis and injury prevention in performers. However, this review aims to critically analyze the emerging contribution of physiological-based literature linked to fast bowling in cricket, highlight the current evidence related to simulated and competitive in-match performance, and relate this practically to the conditioning coach. Furthermore, the review considers limitations with past research and possible avenues for future investigation. It is clear with the advent of new applied mobile monitoring technology that there is scope for more ecologically valid and longitudinal exploration capturing in-match data, providing quantification of physiological workloads, and analysis of the physical demands across the differing formats of the game. Currently, strength and conditioning specialists do not have a critical academic resource with which to shape professional practice, and this review aims to provide a starting point for evidence in the specific area.

Bacterially induced calcium carbonate precipitation and strontium coprecipitation in a porous media flow system.

Strontium-90 is a principal radionuclide contaminant in the subsurface at several Department of Energy sites in the Western U.S., causing a threat to groundwater quality in areas such as Hanford, WA. In this work, we used laboratory-scale porous media flow cells to examine a potential remediation strategy employing coprecipitation of strontium in carbonate minerals. CaCO(3) precipitation and strontium coprecipitation were induced via ureolysis by Sporosarcina pasteurii in two-dimensional porous media reactors. An injection strategy using pulsed injection of calcium mineralization medium was tested against a continuous injection strategy. The pulsed injection strategy involved periods of lowered calcite saturation index combined with short high fluid velocity flow periods of calcium mineralization medium followed by stagnation (no-flow) periods to promote homogeneous CaCO(3) precipitation. By alternating the addition of mineralization and growth media the pulsed strategy promoted CaCO(3) precipitation while sustaining the ureolytic culture over time. Both injection strategies achieved ureolysis with subsequent CaCO(3) precipitation and strontium coprecipitation. The pulsed injection strategy precipitated 71-85% of calcium and 59% of strontium, while the continuous injection was less efficient and precipitated 61% of calcium and 56% of strontium. Over the 60 day operation of the pulsed reactors, ureolysis was continually observed, suggesting that the balance between growth and precipitation phases allowed for continued cell viability. Our results support the pulsed injection strategy as a viable option for ureolysis-induced strontium coprecipitation because it may reduce the likelihood of injection well accumulation caused by localized mineral plugging while Sr coprecipitation efficiency is maintained in field-scale applications.

Potential CO2 leakage reduction through biofilm-induced calcium carbonate precipitation.

Mitigation strategies for sealing high permeability regions in cap rocks, such as fractures or improperly abandoned wells, are important considerations in the long term security of geologically stored carbon dioxide (CO(2)). Sealing technologies using low-viscosity fluids are advantageous in this context since they potentially reduce the necessary injection pressures and increase the radius of influence around injection wells. Using aqueous solutions and suspensions that can effectively promote microbially induced mineral precipitation is one such technology. Here we describe a strategy to homogenously distribute biofilm-induced calcium carbonate (CaCO(3)) precipitates in a 61 cm long sand-filled column and to seal a hydraulically fractured, 74 cm diameter Boyles Sandstone core. Sporosarcina pasteurii biofilms were established and an injection strategy developed to optimize CaCO(3) precipitation induced via microbial urea hydrolysis. Over the duration of the experiments, permeability decreased between 2 and 4 orders of magnitude in sand column and fractured core experiments, respectively. Additionally, after fracture sealing, the sandstone core withstood three times higher well bore pressure than during the initial fracturing event, which occurred prior to biofilm-induced CaCO(3) mineralization. These studies suggest biofilm-induced CaCO(3) precipitation technologies may potentially seal and strengthen fractures to mitigate CO(2) leakage potential.

Engineered applications of ureolytic biomineralization: a review.

Microbially-induced calcium carbonate (CaCO3) precipitation (MICP) is a widely explored and promising technology for use in various engineering applications. In this review, CaCO3 precipitation induced via urea hydrolysis (ureolysis) is examined for improving construction materials, cementing porous media, hydraulic control, and remediating environmental concerns. The control of MICP is explored through the manipulation of three factors: (1) the ureolytic activity (of microorganisms), (2) the reaction and transport rates of substrates, and (3) the saturation conditions of carbonate minerals. Many combinations of these factors have been researched to spatially and temporally control precipitation. This review discusses how optimization of MICP is attempted for different engineering applications in an effort to highlight the key research and development questions necessary to move MICP technologies toward commercial scale applications.

Trace element, rare earth element and trace carbon compounds in Subglacial Lake Whillans, West Antarctica.

Whillans Subglacial Lake (SLW) lies beneath 801 m of ice in the lower portion of the Whillans Ice Stream (WIS) in West Antarctica and is part of an extensive and active subglacial drainage network. Here, the geochemical characterization of SLW rare earth elements (REE), trace elements (TE), free amino acids (FAA), and phenolic compounds (PC) measured in lakewater and sediment porewater are reported. The results show, on average, higher values of REEs in the lakewater than in the porewater, and clear changes in all REE concentrations and select redox sensitive trace element concentrations in porewaters at a depth of ~15 cm in the 38 cm lake sediment core. This is consistent with prior results on the lake sediment redox conditions based on gas chemistry and microbiological data. Low concentrations of vanillyl phenols were measured in the SLW water column with higher concentrations in porewater samples and their concentration profiles in the sediments may also reflect changing redox conditions in the sediments. Vanillin concentrations increased with depth in the sediments as oxygenation decreases, while the concentrations of vanillic acid, the more oxidized component, were higher in the more oxygenated surface sediments. Collectively these results indicate redox changes occurring with the upper 38 cm of sediment in SLW and provide support for the existence of a seawater source, already hypothesized, in the sediments below the lowest measured depth, and of a complex and dynamic geochemical system beneath the West Antarctic Ice Sheet. Our results are the first to detail geochemical properties from an Antarctic subglacial environment using direct sampling technology. Due to their isolation from the wider environment, subglacial lakes represent one of our planets last pristine environments that provide habitats for microbial life and natural biogeochemical cycles but also impact the basal hydrology and can cause ice flow variations.

Metagenome-assembled genomes from High Arctic glaciers highlight the vulnerability of glacier-associated microbiota and their activities to habitat loss.

The rapid warming of the Arctic is threatening the demise of its glaciers and their associated ecosystems. Therefore, there is an urgent need to explore and understand the diversity of genomes resident within glacial ecosystems endangered by human-induced climate change. In this study we use genome-resolved metagenomics to explore the taxonomic and functional diversity of different habitats within glacier-occupied catchments. Comparing different habitats within such catchments offers a natural experiment for understanding the effects of changing habitat extent or even loss upon Arctic microbiota. Through binning and annotation of metagenome-assembled genomes (MAGs) we describe the spatial differences in taxon distribution and their implications for glacier-associated biogeochemical cycling. Multiple taxa associated with carbon cycling included organisms with the potential for carbon monoxide oxidation. Meanwhile, nitrogen fixation was mediated by a single taxon, although diverse taxa contribute to other nitrogen conversions. Genes for sulphur oxidation were prevalent within MAGs implying the potential capacity for sulphur cycling. Finally, we focused on cyanobacterial MAGs, and those within cryoconite, a biodiverse microbe-mineral granular aggregate responsible for darkening glacier surfaces. Although the metagenome-assembled genome of Phormidesmis priestleyi, the cyanobacterium responsible for forming Arctic cryoconite was represented with high coverage, evidence for the biosynthesis of multiple vitamins and co-factors was absent from its MAG. Our results indicate the potential for cross-feeding to sustain P. priestleyi within granular cryoconite. Taken together, genome-resolved metagenomics reveals the vulnerability of glacier-associated microbiota to the deletion of glacial habitats through the rapid warming of the Arctic.

Field based reliability and validity of the bioharness™ multivariable monitoring device.

The Bioharness™ device is designed for monitoring physiological variables in free-living situations but has only been proven to be reliable and valid in a laboratory environment. Therefore, this study aimed to determine the reliability and validity of the Bioharness™ using a field based protocol. Twenty healthy males participated. Heart rate (HR), breathing frequency (BF) and accelerometry (ACC) were assessed by simultaneous measurement of two Bioharness™ devices and a test-retest of a discontinuous incremental walk-jog-run protocol (4 - 11 km·h(-1)) completed in a sports hall. Adopted precision of measurement devices were; HR: Polar T31 (Polar Electro), BF: Spirometer (Cortex Metalyser), ACC: Oxygen expenditure (Cortex Metalyser). For all data, precision of measurement reported good relationships (r = 0.61 to 0.67, p < 0.01) and large Limits of Agreement for HR (>79.2 b·min(-1)) and BF (>54.7 br·min(-1)). ACC presented excellent precision (r = 0.94, p < 0.01). Results for HR (r= ~0.91, p < 0.01: CV <7.6) and ACC (r > 0.97, p < 0.01; CV <14.7) suggested these variables are reliable. BF presented more variable data (r = 0.46-0.61, p < 0.01; CV < 23.7). As velocity of movement increased (>8 km·h(-1)) data became more erroneous. A data cleaning protocol removed gross errors in the data analysis and subsequent reliability and validity statistics improved across all variables. In conclusion, the Bioharness™ HR and ACC variables have demonstrated reliability and validity in a field setting, though data collected at higher velocities should be treated with caution. Measuring human physiological responses in a field based environment allows for more ecologically valid data to be collected and devices such as the Bioharness™ could be used by exercise professionals to begin to further investigate this area.

Diversity, abundance, and potential activity of nitrifying and nitrate-reducing microbial assemblages in a subglacial ecosystem.

Subglacial sediments sampled from beneath Robertson Glacier (RG), Alberta, Canada, were shown to harbor diverse assemblages of potential nitrifiers, nitrate reducers, and diazotrophs, as assessed by amoA, narG, and nifH gene biomarker diversity. Although archaeal amoA genes were detected, they were less abundant and less diverse than bacterial amoA, suggesting that bacteria are the predominant nitrifiers in RG sediments. Maximum nitrification and nitrate reduction rates in microcosms incubated at 4°C were 280 and 18.5 nmol of N per g of dry weight sediment per day, respectively, indicating the potential for these processes to occur in situ. Geochemical analyses of subglacial sediment pore waters and bulk subglacial meltwaters revealed low concentrations of inorganic and organic nitrogen compounds. These data, when coupled with a C/N atomic ratio of dissolved organic matter in subglacial pore waters of ~210, indicate that the sediment communities are N limited. This may reflect the combined biological activities of organic N mineralization, nitrification, and nitrate reduction. Despite evidence of N limitation and the detection of nifH, we were unable to detect biological nitrogen fixation activity in subglacial sediments. Collectively, the results presented here suggest a role for nitrification and nitrate reduction in sustaining microbial life in subglacial environments. Considering that ice currently covers 11% of the terrestrial landmass and has covered significantly greater portions of Earth at times in the past, the demonstration of nitrification and nitrate reduction in subglacial environments furthers our understanding of the potential for these environments to contribute to global biogeochemical cycles on glacial-interglacial timescales.

The Prevalence and Predictors of Hypertension and the Metabolic Syndrome in Police Personnel.

Hypertension and metabolic syndrome (METSYN) are reportedly high in police forces. This may contribute to health deterioration and absenteeism in police personnel. Police forces comprise of staff in 'operational' and 'non-operational' job types but it is not known if job type is associated to hypertension and METSYN prevalence. This study aimed to explore the prevalence of hypertension and METSYN, the factors associated with the risk of hypertension and METSYN, and compare physiological, psychological, and behavioural factors between operational and non-operational police personnel. Cross-sectional data was collected from 77 operational and 60 non-operational police workers. Hypertension and METSYN were prevalent in 60.5% and 20% of operational and 60.0% and 13.6% of non-operational police personnel, respectively (p > 0.05). Operational job type, moderate organisational stress (compared with low stress) and lower high-density lipoprotein cholesterol were associated with lower odds of hypertension, whereas increasing body mass index was associated with increased odds of hypertension (p < 0.05). None of the independent variables were significantly associated with the odds of METSYN. Operational police had several increased cardiometabolic risk markers compared with non-operational police. Given the high prevalence of hypertension and METSYN in operational and non-operational personnel, occupational health interventions are needed for the police and could be informed by the findings of this study.

Thermodynamic and Kinetic Parameters for Calcite Nucleation on Peptoid and Model Scaffolds: A Step toward Nacre Mimicry.

The production of novel composite materials, assembled using biomimetic polymers known as peptoids (N-substituted glycines) to nucleate CaCO3, can open new pathways for advanced material design. However, a better understanding of the heterogeneous CaCO3 nucleation process is a necessary first step. We determined the thermodynamic and kinetic parameters for calcite nucleation on self-assembled monolayers (SAMs) of nanosheet-forming peptoid polymers and simpler, alkanethiol analogues. We used nucleation rate studies to determine the net interfacial free energy (γ net) for the peptoid-calcite interface and for SAMs terminated with carboxyl headgroups, amine headgroups, or a mix of the two. We compared the results with γ net determined from dynamic force spectroscopy (DFS) and from density functional theory (DFT), using COSMO-RS simulations. Calcite nucleation has a lower thermodynamic barrier on the peptoid surface than on carboxyl and amine SAMs. From the relationship between nucleation rate (J 0) and saturation state, we found that under low-saturation conditions, i.e. <3.3 (pH 9.0), nucleation on the peptoid substrate was faster than that on all of the model surfaces, indicating a thermodynamic drive toward heterogeneous nucleation. When they are taken together, our results indicate that nanosheet-forming peptoid monolayers can serve as an organic template for CaCO3 polymorph growth.

Full gait cycle analysis of lower limb and trunk kinematics and muscle activations during walking in participants with and without ankle instability.

BACKGROUND: Chronic ankle instability (CAI) has previously been linked to altered lower limb kinematics and muscle activation characteristics during walking, though little research has been performed analysing the full time-series across the stance and swing phases of gait. RESEARCH QUESTION: The aim of this study was to compare trunk and lower limb kinematics and muscle activity between those with chronic ankle instability and healthy controls. METHODS: Kinematics and muscle activity were measured in 18 (14 males, 4 females) healthy controls (age 22.4 ±â€¯3.6 years, height 177.8 ±â€¯7.6 cm, mass 70.4 ±â€¯11.9 kg, UK shoe size 8.4 ±â€¯1.6), and 18 (13 males, 5 females) participants with chronic ankle instability (age 22.0 ±â€¯2.7 years, height 176.8 ±â€¯7.9 cm, mass 74.1 ±â€¯9.6 kg, UK shoe size 8.1 ±â€¯1.9) during barefoot walking trials, using a combined Helen Hayes and Oxford foot model. Surface electromyography (sEMG) was recorded for the tibialis anterior and gluteus medius. Full curve statistical parametric mapping was performed using independent and paired-samples T-tests. RESULTS: No significant differences were observed in kinematic or sEMG variables between or within groups for the duration of the swing phase of gait. A significantly increased forefoot-tibia inversion was seen in the CAI affected limb when compared to the CAI unaffected limb at 4-16% stance (p = 0.039). No other significant differences were observed. SIGNIFICANCE: There appears to be no differences in muscle activation and movement between CAI and healthy control groups. However, participants with CAI exhibited increased inversion patterns during the stance phase of gait in their affected limb compared to their unaffected limb. This may predispose those with CAI to episodes of giving way and further ankle sprains.