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Introduction: There is an absence in the application of standardised epidemiological principles when calculating and reporting on lower extremity amputation (LEA) rates [1]. The rates of minor LEAs in the diabetic population range from 1.2-362.9 per 100,000 and in the population without diabetes 0.9-109.4 per 100,000. The reported rates of major lower limb amputations vary from 5.6-600 per 100,000 in the diabetic population and 3.6-58.7 per 100,000 in the total population [1]. The variation in methodology does not facilitate comparison across populations and time. All studies published using the population from England, UK, describing minor amputations were systematically reviewed and rates and methodologies compared., Method: A systematic search was carried out using (PRISMA) guidelines [2] to reveal primary data of minor lower extremity amputation rates in England between 1988-2018. This was carried out using electronic databases, grey literature and reference list searching. The search yielded eleven studies that were eligible for review., Results: Significant variation in the reporting of minor lower extremity amputation rates across regional and gender groups in England was found. Rates in the diabetic and non-diabetic population varied from 1.2 to 362.9 per 100,000 and 0.9 to 109.4 per 100,000 respectively. This was predominately a result of poorly describing numerator and denominator populations and defining minor amputations differently. As a result, there was an inability to confidently establish regional, gender and time trends., Conclusion: The inconsistent nature of reporting minor amputations makes drawing conclusions on temporal and population change difficult. Future studies should describe and present basic numerator and denominator population characteristics e.g. number, age and sex and use the standard definition of minor amputation as one that is at or below the ankle., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Forest ecosystems face increasing wildfire threats, demanding prompt and precise detection methods to ensure efficient fire control. However, real-time forest fire data accessibility and timeliness require improvement. Our study addresses the challenge through the introduction of the Unmanned Aerial Vehicles (UAVs) based forest fire database (UAVs-FFDB), characterized by a dual composition. Firstly, it encompasses a collection of 1653 high-resolution RGB raw images meticulously captured utilizing a standard S500 quadcopter frame in conjunction with a RaspiCamV2 camera. Secondly, the database incorporates augmented data, culminating in a total of 15560 images, thereby enhancing the diversity and comprehensiveness of the dataset. These images were captured within a forested area adjacent to Adana Alparslan Türkeş Science and Technology University in Adana, Turkey. Each raw image in the dataset spans dimensions from 353 × 314 to 640 × 480, while augmented data ranges from 398 × 358 to 640 × 480, resulting in a total dataset size of 692 MB for the raw data subset. In contrast, the augmented data subset accounts for a considerably larger size, totaling 6.76 GB. The raw images are obtained during a UAV surveillance mission, with the camera precisely angled a -180-degree to be horizontal to the ground. The images are taken from altitudes alternating between 5 - 15 meters to diversify the field of vision and to build a more inclusive database. During the surveillance operation, the UAV speed is 2 m/s on average. Following this, the dataset underwent meticulous annotation using the advanced annotation platform, Makesense.ai, enabling accurate demarcation of fire boundaries. This resource equips researchers with the necessary data infrastructure to develop innovative methodologies for early fire detection and continuous monitoring, enhancing efforts to protect ecosystems and human lives while promoting sustainable forest management practices. Additionally, the UAVs-FFDB dataset serves as a foundational cornerstone for the advancement and refinement of state-of-the-art AI-based methodologies, aiming to automate fire classification, recognition, detection, and segmentation tasks with unparalleled precision and efficacy., (© 2024 The Author(s).)

The urgent necessity for highly sensitive diagnostic tools has been accentuated by the ongoing mpox (monkeypox) virus pandemic due to the complexity in identifying asymptomatic and presymptomatic carriers. Traditional polymerase chain reaction-based tests, despite their effectiveness, are hampered by limited specificity, expensive and bulky equipment, labor-intensive operations, and time-consuming procedures. In this study, we present a clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12a-based diagnostic platform with a surface plasmon resonance-based fiber tip (CRISPR-SPR-FT) biosensor. The compact CRISPR-SPR-FT biosensor, with a 125 μm diameter, offers high stability and portability, enabling exceptional specificity for mpox diagnosis and precise identification of samples with a fatal mutation site (L108F) in the F8L gene. The CRISPR-SPR-FT system can analyze viral double-stranded DNA from mpox virus without amplification in under 1.5 h with a limit of detection below 5 aM in plasmids and about 59.5 copies/μL when in pseudovirus-spiked blood samples. Our CRISPR-SPR-FT biosensor thus offers fast, sensitive, portable, and accurate target nucleic acid sequence detection.

Coral reefs species represent one-third of all marine species described in the ocean. They are also responsible for providing habitat and support to different species. Recently, Caribbean coral reefs ecosystems have suffered an alarming decrease in their populations as a result of overexploitation. Madracis auretenra in particular, is a widespread shallow coral in marine protected areas (MPAs) of the Caribbean. Due to the important role of MPAs as a biodiversity conservation tool, this species can be used as a model to estimate its dispersion/migration among Caribbean reefs through the use of informative genetic markers (microsatellites) specifically designed for it. Seventeen new polymorphic microsatellites markers for M. auretenra were developed and tested in 330 samples from Colombia, Guatemala, Curacao and Barbados. The gene diversity (1-D) ranged from 0.482 to 0.903, while the evenness ranged from 0.456 to 0.884 after clone removal. The expected heterozygosity (He) ranged from 0.347 to 0.742, while the observed heterozygosity (Ho) ranged from 0.078 to 0.578. The specificity of our microsatellites shows the potential use of these markers in a-posteriori analysis to detect population structure at different spatial scales, where M. auretenra is reported., Competing Interests: The authors have declared that no competing interests exist.

In 2013 Colombia made an important step towards the construction and management of Marine Protected Areas (MPAs) by establishing the first Deep Corals National Park (PNNCP). Inside this MPA, the coral Madracis myriaster (Cnidaria: Pocilloporidae) was found as the main reef builder, offering habitat for many species of fish and invertebrates. In order to improve the study of deep-sea coral habitats, their connectivity and prospective management, nine new genetic markers (microsatellites) were developed for M. myriaster and tested in samples from PNNCP. We present the assessment of these markers, with a specificity for the deep coral, and its prospective use in future analysis for the PNNCP and other areas in the Caribbean and the Atlantic, where M. myriaster is reported. We also include an additional taxonomic analysis performed on samples of M. myriaster using scanning electron microscopy., (© 2022. The Author(s).)

The genetic modification of stem cells (SCs) is typically achieved using integrating vectors, whose potential integrative genotoxicity and propensity for epigenetic silencing during differentiation limit their application. The genetic modification of cells should provide sustainable levels of transgene expression, without compromising the viability of a cell or its progeny. We developed nonviral, nonintegrating, and autonomously replicating minimally sized DNA nanovectors to persistently genetically modify SCs and their differentiated progeny without causing any molecular or genetic damage. These DNA vectors are capable of efficiently modifying murine and human pluripotent SCs with minimal impact and without differentiation-mediated transgene silencing or vector loss. We demonstrate that these vectors remain episomal and provide robust and sustained transgene expression during self-renewal and targeted differentiation of SCs both in vitro and in vivo through embryogenesis and differentiation into adult tissues, without damaging their phenotypic characteristics., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: The SARS-Cov-2 virus (commonly known as COVID-19) has resulted in substantial casualties in many countries. The first case of COVID-19 was reported in China towards the end of 2019. Cases started to appear in several other countries (including Pakistan) by February 2020. To analyze the spreading pattern of the disease, several researchers used the Susceptible-Infectious-Recovered (SIR) model. However, the classical SIR model cannot predict the death rate., Objective: In this article, we present a Death-Infection-Recovery (DIR) model to forecast the virus spread over a window of one (minimum) to fourteen (maximum) days. Our model captures the dynamic behavior of the virus and can assist authorities in making decisions on non-pharmaceutical interventions (NPI), like travel restrictions, lockdowns, etc., Method: The size of training dataset used was 134 days. The Auto Regressive Integrated Moving Average (ARIMA) model was implemented using XLSTAT (add-in for Microsoft Excel), whereas the SIR and the proposed DIR model was implemented using python programming language. We compared the performance of DIR model with the SIR model and the ARIMA model by computing the Percentage Error and Mean Absolute Percentage Error (MAPE)., Results: Experimental results demonstrate that the maximum% error in predicting the number of deaths, infections, and recoveries for a period of fourteen days using the DIR model is only 2.33%, using ARIMA model is 10.03% and using SIR model is 53.07%., Conclusion: This percentage of error obtained in forecasting using DIR model is significantly less than the% error of the compared models. Moreover, the MAPE of the DIR model is sufficiently below the two compared models that indicates its effectiveness., Competing Interests: The authors declare that there is no conflict of interest in any aspect., (Published by Elsevier B.V.)

Aging populations in developed countries will increase the demand for implantable materials to support tissue regeneration. Whey Protein Isolate (WPI), derived from dairy industry by-products, can be processed into hydrogels with the following desirable properties for applications in tissue engineering: (i) ability to support adhesion and growth of cells; (ii) ease of sterilization by autoclaving and (iii) ease of incorporation of poorly water-soluble drugs with antimicrobial activity, such as phloroglucinol (PG), the fundamental phenolic subunit of marine polyphenols. In this study, WPI hydrogels were enriched with PG at concentrations between 0 and 20% w/v. PG solubilization in WPI hydrogels is far higher than in water. Enrichment with PG did not adversely affect mechanical properties, and endowed antimicrobial activity against a range of bacteria which occur in healthcare-associated infections (HAI). WPI-PG hydrogels supported the growth of, and collagen production by human dental pulp stem cells and - to a lesser extent - of osteosarcoma-derived MG-63 cells. In summary, enrichment of WPI with PG may be a promising strategy to prevent microbial contamination while still promoting stem cell attachment and growth., (Copyright © 2021 Elsevier B.V. All rights reserved.)

This study was designed to examine the physiological changes caused by long-term training in a world class female tennis player in preparation for a major championship. Additionally, we aim to describe the training interventions and determine a suitable cooling strategy that was to be used at the 2004 Paralympic Games. The athlete underwent regular physiological assessment during 2003-2004. Physiological measures involved body composition, submaximal and peak oxygen uptake and key variables associated with maximal sprinting. In addition, a suitable match-play cooling intervention and hydration strategy was also explored. Body composition improved over the course of the study. Aerobic capacity fell by 21%, yet the submaximal physiological variables such as lactate profile and pushing economy improved. The trade off of aerobic capacity was perhaps noticeably counter-balanced with the maintenance of the peak sprinting speed and improvement found in the fatigue profile across ten repeated sprints. The extensive training programme was responsible for these changes and these adaptations resulted in a more confident athlete, in peak physical condition leading into the Paralympic Games. It is difficult to appreciate the extent to which this work had an impact on tennis performance given the skill requirements of wheelchair tennis and this warrants future attention. Key pointsPhysiological adaptations were apparent over the two-year training period.The training emphasis resulted in a reduction in aerobic capacity, yet an improvement in repetitive sprint performance was seen leading into the Major competition.An effective cooling technique was identified that could be used during wheelchair tennis performance.The athlete and coaches were complimentary to the physiological support provided, which resulted in a more confident athlete at the Paralympic Games.

Older people may operate much closer to their maximum capabilities than young adults when ascending stairs due to their lower maximum musculoskeletal capabilities. The purpose of this study was to establish the joint moment and range of motion demands of stair ascent relative to maximum capabilities in elderly and young adults. Fifteen elderly (mean age 75 years) and 17 young adult (mean age 25 years) participants ascended a purpose-built 4-step staircase with force platforms embedded into the steps and kinematic data was acquired using motion capture. Maximum musculoskeletal capabilities were assessed using a dynamometer. This study showed for the first time that stair ascent approaches the joint moment limits at the ankle in both young and older participants ( approximately 90%). One of the most important and novel findings of this study was that elderly people were only capable of meeting the high demands by adopting a number of alternative strategies not observed in young adults: (i) applying the joint moments differently than young adults across the knee and ankle, (ii) translocating energy from the knee to the ankle, thereby enhancing the ankle joint moment upon maximum demand and (iii) by enabling the plantarflexors to act over a more favourable portion of the moment-angle relation upon maximum ankle joint moment demand. The elderly displayed a more cautious strategy to optimize positional stability during stair ascent, by maintaining a smaller separation between the centre of mass and centre of pressure in the frontal plane. It seems that elderly people may meet the demands of unaided stair ascent by adopting a number of alternative strategies to compensate for their reduced musculoskeletal capabilities.

The purpose of this study was to examine the role of wheeling experience on efficiency, metabolic cost, and differentiated ratings of perceived exertion (RPEs) during synchronous and asynchronous hand-rim propulsion with varying arm frequencies. Fourteen able-bodied (AB) male participants and 8 male wheelchair sportsmen (WS) performed tests of peak oxygen consumption for both propulsion modes. Subsequently, 2 series of five 4-min sub-maximal exercise bouts were completed at an individualized velocity (60% of peak oxygen consumption). Arm frequencies consisted of the freely chosen frequency (FCF), followed by 4 counter-balanced paced trials pushing at 60%, 80%, 120%, and 140% of the FCF. Efficiency indices (gross, GE; work, WE) were determined and peripheral (RPE-P), central (RPE-C), and overall (RPE-O) RPEs were recorded. The GE (6.4% vs. 8.4%) and WE (11.3% vs. 15.1%) were significantly higher in WS than in AB (p = 0.001). Trends in the oxygen consumption, GE, and WE data were similar in both groups, propulsion mode, and arm frequency. Data suggest that 80% FCF resulted in improved efficiency for both propulsion mode and group, although the differences between those arm frequencies immediately above and below were non-significant. Lower RPE scores corresponded with higher efficiency values. Regardless of group there were significant differences (p = 0.001) between the differentiated RPE measures, whereby RPE-P was on average always the highest score (13.1) and RPE-C the lowest (11.1; RPE-O was 12.2). In conclusion, despite the anticipated differences in efficiency between the WS and AB participants, this study confirmed that psycho-physiological measures produce similar trends to physiological measures with manipulations of both arm frequency and propulsion mode.

The high incidence of falls in older adults during stair negotiation suggests that this task is physically challenging and potentially dangerous. The present study aimed to examine the influence of light handrail use on the biomechanics of stair negotiation in old age. Thirteen older adults ascended and descended a purpose-built staircase at their self-selected speed: (i) unaided and (ii) with light use of the handrails. Ground reaction forces (GRFs) were measured from force platforms mounted into each step and motion capture was used to collect kinematic data. Knee and ankle joint moments were calculated using the kinetic and kinematic data. The horizontal separation between the centre of mass (COM) and the centre of pressure (COP) was assessed in the sagittal and frontal planes. During stair ascent, handrail use caused a different strategy to be employed compared to unaided ascent with a redistribution of joint moments. Specifically, the ankle joint moment (of the trailing leg) was reduced with handrail use, which has previously been shown to approach its limits during unaided stair ascent, but the knee joint moment (of the leading leg) increased. Previous research has shown that a larger joint moment reserve is available at the knee during unaided stair ascent. During stair descent, the ankle joint moment increased with handrail use, this was associated, however, with a more effective control of balance as shown by a reduced COM-COP separation in the direction of progression compared to unaided descent. These results indicate that although the biomechanical mechanisms are different for stair ascent and descent, the safety of stair negotiation is improved for older adults with light use of the handrails.

The purpose of this study was to examine the effectiveness of reducing core temperature in postexercise hyperthermic subjects and to assess if hand cooling (HC) improves subsequent timed distance performance. Following a detailed measurement check on the use of insulated auditory canal temperature (T(ac)), eight wheelchair (WA) athletes and seven male able-bodied (AB) athletes performed two testing sessions, comprising a 60-min exercise protocol and 10-min recovery period, followed by a performance trial (1 km and 3 km for WA and AB, respectively) at 30.8 degrees C (SD 0.2) and 60.6% (SD 0.2) relative humidity. In a counterbalanced order, HC and a no-cooling condition was administered during the 10-min recovery period before the performance trial. Nonsignificant condition x time interactions for both WA (F(15,75) = 1.5, P = 0.14) and AB (F(15,90) = 1.2, P = 0.32) confirmed that the exercise-induced changes (Delta) in T(ac) were similar before each intervention. However, the exercise-induced increase was evidently greater in AB compared with WA (2.0 vs. 1.3 degrees C change, respectively). HC produced DeltaT(ac) of -0.4 degrees C (SD 0.4) and -1.2 degrees C (SD 0.2) in comparison (WA and AB, respectively), and simple-effects analyses suggested that the reductions in T(ac) were noteworthy after 4 min of HC. HC had an impact on improving AB performances by -4.0 s (SD 11.5) (P < 0.05) and WA by -20.5 s (SD 24.2) (P > 0.05). In conclusion, extraction of heat through the hands was effective in lowering T(ac) in both groups and improving 3-km performance in the AB athletes and trends toward positive gains for the 1-km performance times of the WA group.

In this study, we aimed to establish the joint moment and joint range of motion requirements of stair descent and the demands relative to maximal capacities in elderly and young adults. Participants descended a custom-built standard dimension four-step staircase, at their self-selected speed in a step-over manner. Kinetic data were acquired from force platforms embedded into each of the steps and into the floor at the base of the stairs. A motion analysis system was used to acquire kinematic data and joint moments were calculated using the kinematic and kinetic data. Maximum capacities (joint moment and joint range of motion) were assessed using a dynamometer. During stair descent the elderly generated lower absolute ankle joint moments than the young, which enabled them to operate at a similar relative proportion of their maximal capacity compared to young adults (75%). The knee joint moments during stair descent were similar between groups, but the elderly operated at a higher proportion of their maximal capacity (elderly: 42%; young: 30%). Ankle plantarflexion-dorsiflexion angle changes were similar between groups, which meant that the elderly operated at a higher proportion of their maximal assisted dorsiflexion angle. These results indicate that the elderly redistribute the joint moments in order to maintain the task demands within 'safe' limits.

The purpose of this study was to determine the effect of crank length and cadence on mechanical efficiency in hand cycling. Eight wheelchair dependent, high performance athletes completed four 4-min submaximal exercise bouts at a constant power output of 90 W over the different experimental conditions (crank length, pedal rate) using a sports hand bike (Draft, Godmanchester, UK). Two different crank lengths (180 and 220 mm) were tested at two different cadences (70 and 85 rev min(-1)) using the synchronous mode of cranking. Physiological measures of oxygen uptake (VO2) minute ventilation, blood lactate (B[La]), heart rate (HR), rate of perceived exertion (RPE) were recorded, gross (GE) and net (NE) efficiency were calculated. A two-way ANOVA with repeated measures was applied to determine the effects of crank length, cadence and their interaction on these physiological measures. Both GE and NE were significantly higher and V(O)(2) significantly lower for the 180 mm crank (P < 0.05). No significant main effect was found for cadence on the physiological measures (P > 0.05). Likewise, no interactions between crank length and pedal rate were found. There was however, a trend observed with HR and B[La] often lower with the 180 mm crank, indicating lower physiological stress. The RPE data supported this finding, with a tendency for lower ratings with the 180 mm crank (9 +/- 2 vs. 10 +/- 3). The short crank length when used at 85 rev min(-1) was found to be the most efficient (GE 21.4 +/- 3.1%). In conclusion, crank length has a significant effect on ME in hand cycling. A shorter crank length of 180 mm was found to be more efficient than the 220 mm, regardless of pedal rate during hand cycling.

Background: The aim of this study was to investigate the architectural alterations of skeletal muscle following hemiplegic cerebral palsy. If associated with functional and clinical measures of disability, information on muscle architecture could then be used as an objective tool in the assessment of motor disability in these patients., Methods: Ultrasonography was used to assess in vivo the gastrocnemius muscle architecture in the paretic and non-paretic legs of eight children with cerebral palsy., Findings: Fascicle length and muscle thickness at the resting ankle position were reduced in the paretic compared to the non-paretic legs by up to 18% and 20%, respectively (P<0.05), indicating a loss of both in-series and in-parallel sarcomeres in the affected muscles. However, pennation angle was similar (P>0.05) in the two legs., Interpretation: The present results indicate that paresis in hemiplegic cerebral palsy may affect the geometry of skeletal muscle. Further studies are required to examine the relation between muscle architecture, severity of motor disability, and treatment.

On an upland moor dominated by pioneer Calluna vulgaris and with an understorey of mosses and lichens, experimental plots were treated with factorial combinations of nitrogen (N) at +0 and +20kg Nha(-1)yr(-1), and phosphorus (P) at +0 and +5kg Pha(-1)yr(-1). Over the 4-year duration of the experiment, the cover of the Calluna canopy increased in density over time as part of normal phenological development. Moss cover increased initially in response to N addition but then remained static; increases in cover in response to P addition became stronger over time, eventually causing reductions in the cover of the dominant Calluna canopy. Lichen cover virtually disappeared within 4 years in plots receiving +20kg Nha(-1)yr(-1) and also in separate plots receiving +10kg Nha(-1)yr(-1), but this effect was reversed by the addition of P.

Muscles and tendons are highly adaptive tissues in response to chronic changes in loading and to aging. A remarkable reorganization in muscle architecture occurs in both conditions together with significant alterations in tendon mechanical properties. This review discusses the possible mechanisms underlying these myotendinous changes and the influence thereof on the behavior of the muscle-tendon complex as a whole.

Muscle weakness experienced in old age has many detrimental consequences for activities of daily life. Given the serious problems presented by weakness in old age, strategies to prevent or mitigate this process are of paramount importance. In recent years resistance training has emerged as an effective method for increasing strength in the elderly. Despite this, little is known regarding the muscular, neural and tendinous adaptations that occur with resistance training in old age. Hence, we have conducted a series of experiments to investigate these adaptations. We have found increases in maximal isometric and concentric torque by 9-37% after resistance training in older people (65-81 years). Associated with these strength gains were increases in agonist muscle neural drive without any change in the co-activation of antagonist muscles. Resistance training can cause increases in muscle size and also adaptations to the internal muscle structure. Tendons of older adults adapt to resistance training by increasing their stiffness and Young's modulus. In conclusion, many of the musculoskeletal factors characterizing ageing can be at least partially mitigated by resistance training.

Background: Participation in wheelchair sports such as tennis and rugby enables people with quadriplegia to compete both individually and as a team at the highest level. Both sports are dominated by frequent, intermittent, short term power demands superimposed on a background of aerobic activity., Objective: To gain physiological profiles of highly trained British quadriplegic athletes, and to examine the relation between aerobic and sprint capacity., Methods: Eight male quadriplegic athletes performed an arm crank exercise using an ergometer fitted with a Schoberer Rad Messtechnik (SRM) powermeter. The sprint test consisted of three maximum-effort sprints of five seconds duration against a resistance of 2%, 3%, and 4% of body mass. The highest power output obtained was recorded (PPO). Peak oxygen consumption (V(O2peak)), peak heart rate (HR(peak)), and maximal power output (PO(aer)) were determined., Results: Mean PO(aer) was 67.7 (16.2) W, mean V(O2peak) was 0.96 (0.17) litres/min, and HR(peak) was 134 (19) beats/min for the group. There was high variability among subjects. Peak power over the five second sprint for the group was 220 (62) W. There was a significant correlation between V(O2peak) (litres/min) and PO(aer) (W) (r = 0.74, p<0.05)., Conclusions: These British quadriplegic athletes have relatively high aerobic fitness when compared with the available literature. Moreover, the anaerobic capacity of these athletes appeared to be relatively high compared with paraplegic participants.

The age-related loss of muscle mass known as senile sarcopenia is one of the main determinants of frailty in old age. Molecular, cellular, nutritional and hormonal mechanisms are at the basis of sarcopenia and are responsible for a progressive deterioration in skeletal muscle size and function. Both at single-fibre and at whole-muscle level, the loss of force exceeds that predicted by the decrease in muscle size. For single fibres, the loss of intrinsic force is mostly due to a loss in myofibrillar protein content. For whole muscle, in addition to changes in neural drive, alterations in muscle architecture and in tendon mechanical properties, exemplified by a reduction in tendon stiffness, have recently been shown to contribute to this phenomenon. Resistance training can, however, cause substantial gains in muscle mass and strength and provides a protective effect against several of the cellular and molecular changes associated with muscle wasting and weakness. In old age, not only muscles but also tendons are highly responsive to training, since an increase in tendon stiffness has been observed after a period of increased loading. Many of the myotendinous factors characterizing ageing can be at least partly reversed by resistance training.

Tendons primarily function as contractile force transmitters, but their mechanical properties may change dependent upon their level of mechanical usage. Using an ultrasound-based technique we have assessed tendon mechanical properties in vivo in a number of conditions representing different levels of mechanical usage. Ageing alters tendon mechanical properties; stiffness and modulus were lower in older adults by 10 and 14%, respectively, compared to young adults. Increased levels of exercise loading in old age can however partly reverse this process, as tendon stiffness and modulus were found to increase by 65 and 69%, respectively. Complete unloading due to bed rest or spinal cord injury both reduce tendon stiffness and modulus, however, only chronic unloading due to spinal cord injury seems to cause tendon atrophy. Alterations in tendon mechanical properties due to changes in the levels loading have implications for the speed of force transmission, the muscle's operating range and the likelihood of tendon strain injury.

This study was designed to investigate the effect of long-term (11 years) ammonium nitrate additions on standing mass, nutrient content (% and kg ha(-1)), and the proportion of the added N retained within the different compartments of the system. The results showed that more than 90% of all N in the system was found in the soil, particularly in the organic (Oh) horizon. Added N increased the standing mass of vegetation and litter and the N content (kg N ha(-1)) of almost all measured plant, litter and soil compartments. Green tissue P and K content (kg ha(-1)) were increased, and N:P ratios were increased to levels indicative of P limitation. At the lowest treatment, most of the additional N was found in plant/litter compartments, but at higher treatments, there were steep increases in the amount of additional N in the underlying organic and mineral (Eag) horizons. The budget revealed that the proportion of added N found in the system as a whole increased from 60%, 80% and up to 90% in response to the 40, 80 and 120 kg N ha(-1) year(-1) treatments, respectively.

The loss of muscle mass associated with ageing only partly explains the observed decline in muscle strength. This paper provides evidence of the contribution of muscular, tendinous and neural alterations to muscle weakness in old age and discusses the complex interplay between the changes of the contractile tissue with those of the tendinous tissue in relation to the mechanical behavior of the muscle as a whole. Despite the considerable structural and functional alterations, the elderly musculoskeletal system displays remarkable adaptability to training in old age and many of these adverse effects may be substantially mitigated, if not reversed, by resistive loading. The interplay between these muscular and tendinous adaptations has an impact both on the length-force and force-velocity relationships of the muscle and is likely to affect the range of motion, rate of force development, maximum force development and speed of movement of the older individual.

While microgravity exposure is known to cause deterioration of skeletal muscle performance, little is known regarding its effect on tendon structure and function. Hence, the aims of this study were to investigate the effects of simulated microgravity on the mechanical properties of human tendon and to assess the effectiveness of resistive countermeasures in preventing any detrimental effects. Eighteen men (aged 25-45 yr) underwent 90 days of bed rest: nine performed resistive exercise during this period (BREx group), and nine underwent bed rest only (BR group). Calf-raise and leg-press exercises were performed every third day using a gravity-independent flywheel device. Isometric plantar flexion contractions were performed by using a custom-built dynamometer, and ultrasound imaging was used to determine the tensile deformation of the gastrocnemius tendon during contraction. In the BR group, tendon stiffness estimated from the gradient of the tendon force-deformation relation decreased by 58% (preintervention: 124 +/- 67 N/mm; postintervention: 52 +/- 28 N/mm; P < 0.01), and the tendon Young's modulus decreased by 57% postintervention (P < 0.01). In the BREx group, tendon stiffness decreased by 37% (preintervention: 136 +/- 66 N/mm; postintervention: 86 +/- 47 N/mm; P < 0.01), and the tendon Young's modulus decreased by 38% postintervention (P < 0.01). The relative decline in tendon stiffness and Young's modulus was significantly (P < 0.01) greater in the BR group compared with the BREx group. Unloading decreased gastrocnemius tendon stiffness due to a change in tendon material properties, and, although the exercise countermeasures did attenuate these effects, they did not completely prevent them. It is suggested that the total loading volume was not sufficient to completely prevent alterations in tendon mechanical properties.

This study determined the effects of increased N deposition on rates of N and P transformations in an upland moor. The litter layer and the surface of the organic Oh horizon were taken from plots that had received long-term additions of ammonium nitrate at rates of 40, 80 and 120 kg N ha(-1) yr(-1). Net mineralisation processes were measured in both field and laboratory incubations. Soil phosphomonoesterase (PME) activity and rates of N(2)O release were measured in laboratory incubations and root-surface PME activity measured in laboratory microcosms using Calluna vulgaris bioassay seedlings. Net mineralisation rates were relatively slow, with net ammonification consistently stimulated by N addition. Net nitrification was marginally stimulated by N addition in the laboratory incubation. N additions also increased soil and root-surface (PME) activity and rates of N(2)O release. Linear correlations were found between litter C:N ratio and all the above processes except net nitrification in field incubations. When compared with data from a survey of European forest sites, values of litter C:N ratio were greater than a threshold below which substantial, N input-related increases in net nitrification rates occurred. The maintenance of high C:N ratios with negligible rates of net nitrification was associated with the common presence of ericaceous litter and a mor humus layer in both this moorland as well as the forest sites.

This study was designed to investigate the leaching response of an upland moorland to long-term (10 yr) ammonium nitrate additions of 40, 80 and 120 kg N ha(-1) yr(-1) and to relate this response to other indications of potential system damage, such as acidification and cation displacement. Results showed increases in nitrate leaching only in response to high rates of N input, in excess of 96 and 136 kg total N input ha(-1) yr(-1) for the organic Oh horizon and mineral Eag horizon, respectively. Individual N additions did not alter ammonium leaching from either horizon and ammonium was completely retained by the mineral horizon. Leaching of dissolved organic nitrogen (DON) from the Oh horizon was increased by the addition of 40 kg N ha(-1) yr(-1), but in spite of increases, retention of total dissolved nitrogen reached a maximum of 92% and 95% of 80 kg added N ha(-1) yr(-1) in the Oh and Eag horizons, respectively. Calcium concentrations and calcium/aluminium ratios were decreased in the Eag horizon solution with significant acidification mainly in the Oh horizon leachate. Nitrate leaching is currently regarded as an early indication of N saturation in forest systems. Litter C:N ratios were significantly lowered but values remained above a threshold predicted to increase leaching of N in forests.

This study investigated changes in elderly muscle joint angle-torque relation induced by resistance training. Older adults were assigned to either training (n = 9, age 74.3 +/- 3.5 years; mean +/-s.d.) or to control groups (n = 9, age 67.1 +/- 2 years). Leg-extension and leg-press exercises were performed three times per week for 14 weeks. Maximal isometric knee extension torque was measured across the knee joint angle range of movement. Vastus lateralis muscle architecture was examined in vivo using ultrasonography. The vastus lateralis muscle fascicle force was estimated from the measured joint torque, enabling construction of the fascicle length-force relation. Electromyographic (EMG) activity was measured from representative agonist and antagonist muscles. Training altered the angle-torque relation: (a) displacing it by 9-31% towards higher torque values (P < 0.05); and (b) shifting the optimal angle from 70 deg (corresponding torque: 121.4 +/- 61 N m) before to 60 deg (134.2 +/- 57.2 N m; P < 0.05) after training. Training also altered the fascicle length-force relation: (a) displacing it by 11-35% towards higher force values; and (b) shifting the optimal fascicle length from 83.7 +/- 8 mm (corresponding force: 847.9 +/- 365.3 N) before to 93.2 +/- 12.5 mm (939.3 +/- 347.8 N; P < 0.01) after training. The upward displacement of the angle-torque relation was mainly due to a training-induced increase in agonist activation, whilst the shift in the optimal angle was associated with changes in muscle-tendon properties.

This study assessed muscle-specific force in vivo following strength training in old age. Subjects were assigned to training (n = 9, age 74.3 +/- 3.5 yr; mean +/- SD) and control (n = 9, age 67.1 +/- 2 yr) groups. Leg-extension and leg-press exercises (2 sets of 10 repetitions at 80% of the 5 repetition maximum) were performed three times/wk for 14 wk. Vastus lateralis (VL) muscle fascicle force was calculated from maximal isometric voluntary knee extensor torque with superimposed stimuli, accounting for the patella tendon moment arm length, ultrasound-based measurements of muscle architecture, and antagonist cocontraction estimated from electromyographic activity. Physiological cross-sectional area (PCSA) was calculated from the ratio of muscle volume to fascicle length. Specific force was calculated by dividing fascicle force by PCSA. Fascicle force increased by 11%, from 847.9 +/- 365.3 N before to 939.3 +/- 347.8 N after training (P < 0.05). Due to a relatively greater increase in fascicle length (11%) than muscle volume (6%), PCSA remained unchanged (pretraining: 30.4 +/- 8.9 cm(2); posttraining: 29.1 +/- 8.4 cm(2); P > 0.05). Activation capacity and VL muscle root mean square electromyographic activity increased by 5 and 40%, respectively, after training (P < 0.05), indicating increased agonist neural drive, whereas antagonist cocontraction remained unchanged (P > 0.05). The VL muscle-specific force increased by 19%, from 27 +/- 6.3 N/cm(2) before to 32.1 +/- 7.4 N/cm(2) after training (P < 0.01), highlighting the effectiveness of strength training for increasing the intrinsic force-producing capacity of skeletal muscle in old age.