A Scalable CMOS Molecular Electronics Chip for Single-Molecule Biosensing

This work reports the first CMOS molecular electronics chip. It is configured as a biosensor, where the primary sensing element is a single molecule "molecular wire" consisting of a ∼100 GΩ, 25 nm long alpha-helical peptide integrated into a current monitoring circuit. The engineered peptide contains a central conjugation site for attachment of various probe molecules, such as DNA, proteins, enzymes, or antibodies, which program the biosensor to detect interactions with a specific target molecule. The current through the molecular wire under a dc applied voltage is monitored with millisecond temporal resolution. The detected signals are millisecond-scale, picoampere current pulses generated by each transient probe-target molecular interaction. Implemented in a 0.18 μm CMOS technology, 16k sensors are arrayed with a 20 μm pitch and read out at a 1 kHz frame rate. The resulting biosensor chip provides direct, real-time observation of the single-molecule interaction kinetics, unlike classical biosensors that measure ensemble averages of such events. This molecular electronics chip provides a platform for putting molecular biosensing "on-chip" to bring the power of semiconductor chips to diverse applications in biological research, diagnostics, sequencing, proteomics, drug discovery, and environmental monitoring.

Multiplex Single-Molecule Kinetics of Nanopore-Coupled Polymerases

DNA polymerases have revolutionized the biotechnology field due to their ability to precisely replicate stored genetic information. Screening variants of these enzymes for specific properties gives the opportunity to identify polymerases with different features. We have previously developed a single-molecule DNA sequencing platform by coupling a DNA polymerase to an α-hemolysin pore on a nanopore array. Here, we use this approach to demonstrate a single-molecule method that enables rapid screening of polymerase variants in a multiplex manner. In this approach, barcoded DNA strands are complexed with polymerase variants and serve as templates for nanopore sequencing. Nanopore sequencing of the barcoded DNA reveals both the barcode identity and kinetic properties of the polymerase variant associated with the cognate barcode, allowing for multiplexed investigation of many polymerase variants in parallel on a single nanopore array. Further, we develop a robust classification algorithm that discriminates kinetic characteristics of the different polymerase mutants. As a proof of concept, we demonstrate the utility of our approach by screening a library of ∼100 polymerases to identify variants for potential applications of biotechnological interest. We anticipate our screening method to be broadly useful for applications that require polymerases with altered physical properties.

Rugby World Cup 2019 injury surveillance study

Background

Full contact team sports, such as rugby union, have high incidences of injury. Injury surveillance studies underpin player welfare programmes in rugby union.

Objective

To determine the incidence, severity, nature and causes of injuries sustained during the Rugby World Cup 2019.

Methods

A prospective, whole population study following the definitions and procedures recommended in the consensus statement for epidemiologic studies in rugby union. Output measures included players' age (years), stature (cm), body mass (kg), playing position, and group-level incidence (injuries/1000 player-hours), severity (days-absence), injury burden (days absence/1000 player-hours), location (%), type (%) and inciting event (%) of injuries.

Results

Overall incidences of injury were 79.4 match injuries/1000 player-match-hours (95% CI: 67.4 to 93.6) and 1.5 training injuries/1000 player-training-hours (95% CI: 1.0 to 2.3). The overall mean severity of injury was 28.9 (95% CI: 20.0 to 37.8) days absence during matches and 14.8 (95% CI: 4.1 to 25.5) days absence during training. The most common locations and types of match injuries were head/face (22.4%), posterior thigh (12.6%), ligament sprain (21.7%) and muscle strain (20.3%); the ankle (24.0%), posterior thigh (16.0%), muscle strain (44.0%) and ligament sprain (16.0%) were the most common locations and types of injuries during training. Tackling (28.7%), collisions (16.9%) and running (16.9%) were responsible for most match injuries and non-contact (36.0%) and contact (32.0%) rugby skills activities for training injuries.

Conclusion

The incidence, severity, nature and inciting events associated with match and training injuries at Rugby World Cup 2019 were similar to those reported for Rugby World Cups 2007, 2011 and 2015.

Modeling the impact of players' workload on the injury-burden of English Premier League football clubs

The loss of players through injury is known to affect team performance in many sports; it is important, therefore, for professional teams to be able to quantify the likely injury-burden that will be encountered throughout a season. A kinetic model, based on the rates at which match and training injuries are sustained and resolved, a team's squad size and the 2017/2018 season fixture schedule for teams competing in the English Premier League, is used to produce daily forecasts of injury-burden experienced by a typical team. The incidences and median severities of match (incidence: 26.9 injuries/1000 player-match hours, 95% CI: 21.5-33.7; severity: 17.5 days, 95% CI: 13.0-28.0) and training (incidence: 4.3 injuries/1000 player-training hours, 95% CI: 3.4-5.5; severity: 14.0 days, 95% CI: 11.0-22.0) injuries were determined using data collected from four English Premier League football clubs during the 2016/2017 season. Time-to-recovery curves for the match and training injuries sustained in the Premier League closely matched the time-to-recovery curves predicted by the kinetic model used in this study. The kinetic model predicted higher match and lower training injury burdens and a higher overall injury burden for successful teams competing in both national and European club competitions compared to teams competing only in national competitions. The model also showed that, in terms of injury-burden, there were no benefits in adopting a 4-week mid-season break during the season: reducing the number of clubs competing in the Premier League would, however, reduce the overall injury burden during a season.

Consensus statement on epidemiological studies of medical conditions in tennis, April 2009

BACKGROUND

The reported incidence, severity and nature of injuries sustained in tennis vary considerably between studies. While some of these variations can be explained by differences in sample populations and conditions, the main reasons are related to differences in definitions and methodologies employed in the studies.

OBJECTIVE

This statement aims to review existing consensus statements for injury surveillance in other sports in order to establish definitions, methods and reporting procedures that are applicable to the specific requirements of tennis.

DESIGN

The International Tennis Federation facilitated a meeting of 11 experts from seven countries representing a range of tennis stakeholders. Using a mixed methods consensus approach, key issues related to definitions, methodology and implementation were discussed and voted on by the group during a structured 1-day meeting. Following this meeting, two members of the group collaborated to produce a draft statement, based on the group discussions and voting outcomes. Three revisions were prepared and circulated for comment before the final consensus statement was produced.

RESULTS

A definition of medical conditions (injuries and illnesses) that should be recorded in tennis epidemiological studies and criteria for recording the severity and nature of these conditions are proposed. Suggestions are made for recording players' baseline information together with recommendations on how medical conditions sustained during match play and training should be reported.

CONCLUSIONS

The definitions and methodology proposed for recording injuries and illnesses sustained during tennis activities will lead to more consistent and comparable data being collected. The surveillance procedures presented here may also be applicable to other racket sports.

Particulate bioluininescence in dinoflagellates: dissociation and partial reconstitution

With the same extraction conditions used for Gonyaulax polyedra, soluble and particulate bioluminescence can be isolated from two additional species, Pyrodinium bahamense and Pyrocystis lunula. We have been able, for all three species, to dissociate soluble luciferin and luciferase from the particulate system. Luciferin can be incorporated into both reacted and unreacted particulate systems.

Comparison of injuries sustained on artificial turf and grass by male and female elite football players

The objective of this study was to compare incidences and patterns of injury for female and male elite teams when playing football on artificial turf and grass. Twenty teams (15 male, 5 female) playing home matches on third-generation artificial turf were followed prospectively; their injury risk when playing on artificial turf pitches was compared with the risk when playing on grass. Individual exposure, injuries (time loss) and injury severity were recorded by the team medical staff. In total, 2105 injuries were recorded during 246,000 h of exposure to football. Seventy-one percent of the injuries were traumatic and 29% overuse injuries. There were no significant differences in the nature of overuse injuries recorded on artificial turf and grass for either men or women. The incidence (injuries/1000 player-hours) of acute (traumatic) injuries did not differ significantly between artificial turf and grass, for men (match 22.4 v 21.7; RR 1.0 (95% CI 0.9-1.2); training 3.5 v 3.5; RR 1.0 (0.8-1.2)) or women [match 14.9 v 12.5; RR 1.2 (0.8-1.8); training 2.9 v 2.8; RR 1.0 (0.6-1.7)]. During matches, men were less likely to sustain a quadriceps strain (P=0.031) and more likely to sustain an ankle sprain (P=0.040) on artificial turf.

The challenges of sequencing by synthesis

DNA sequencing-by-synthesis (SBS) technology, using a polymerase or ligase enzyme as its core biochemistry, has already been incorporated in several second-generation DNA sequencing systems with significant performance. Notwithstanding the substantial success of these SBS platforms, challenges continue to limit the ability to reduce the cost of sequencing a human genome to $100,000 or less. Achieving dramatically reduced cost with enhanced throughput and quality will require the seamless integration of scientific and technological effort across disciplines within biochemistry, chemistry, physics and engineering. The challenges include sample preparation, surface chemistry, fluorescent labels, optimizing the enzyme-substrate system, optics, instrumentation, understanding tradeoffs of throughput versus accuracy, and read-length/phasing limitations. By framing these challenges in a manner accessible to a broad community of scientists and engineers, we hope to solicit input from the broader research community on means of accelerating the advancement of genome sequencing technology.

An empirical approach for defining acceptable levels of risk: a case study in team sports

OBJECTIVES

To determine acceptable levels of risk in sport and to compare these with values used in occupational settings.

DESIGN

Cross-sectional, questionnaire-based study.

SETTINGS

Seven soccer and 11 rugby union teams.

SUBJECTS

140 male athletes and 108 male and 100 female spectators associated with soccer and rugby union teams.

MAIN OUTCOMES

Views on acceptable frequencies with which athletes sustain acute injuries of various levels of severity.

RESULTS

The responses of athletes and spectators were similar, although spectators consistently indicated a higher acceptable frequency of injury than athletes. There were no significant differences in responses as a function of respondents' gender and age. The results confirmed an inverse relationship between the acceptable frequency of occurrence and the severity of injury, although the relationships identified by the risk-averse and risk-taking minorities within the sample population were widely different.

CONCLUSION

The mean frequency-severity risk relationship identified by athletes and spectators in soccer and rugby was similar to the relationship routinely used for risk assessments in industry and commerce.

Preparticipation medical evaluation in professional sport in the UK: theory or practice?

OBJECTIVE

To determine the level of pre-employment, pre-season, and post-injury medical evaluation of players undertaken within UK professional team sports.

DESIGN

A postal, whole population survey.

SETTING

Elite professional sports teams in England.

POPULATION

Six groups comprising the following clubs: professional football (Premiership, 15 of 20; Championship, 22 of 24), rugby union (Premiership, 9 of 12; Division 1, 11 of 14), rugby league (Super League, 6 of 11) and cricket (County, 12 of 18).

MAIN OUTCOME MEASURES

Number (percentage) of clubs recording players' medical history and undertaking medical examinations of players' cardiovascular, respiratory, neurological, and musculoskeletal systems at pre-employment, pre-season and post-injury.

RESULTS

The overall response to the survey was 74%, with a range from 55% to 92% among groups. Almost 90% of football (Premiership and Championship) and rugby union (Premiership) clubs took a pre-employment history of players' general health, cardiovascular, respiratory, neurological, and musculoskeletal systems, but fewer than 50% of cricket and rugby union (Division 1) clubs recorded a history. The majority of football (Premiership and Championship) and rugby union (Premiership) clubs implemented both cardiovascular and musculoskeletal examinations of players before employment. Fewer than 25% of clubs in any of the groups implemented neurological examinations of players at pre-employment, although 100% of rugby union (Premiership) and rugby league clubs implemented neurological testing during pre-season.

CONCLUSIONS

None of the sports implemented best practice guidelines for the preparticipation evaluation of players at all stages of their employment. Departures from best practice guidelines and differences in practices between clubs within the same sport leave club physicians vulnerable if their players sustain injuries or ill health conditions that could have been identified and avoided through the implementation of a preparticipation examination.

Tackle mechanisms and match characteristics in women's elite football tournaments

BACKGROUND

Several tools have been used for assessing risk situations and for gathering tackle information from international football matches for men but not for women.

PURPOSE

To analyse activities in women's football and to identify the characteristics and risk potentials of tackles.

STUDY DESIGN

Retrospective video analysis.

METHOD

Video recordings of 24 representative matches from six women's top-level tournaments were analysed for tackle parameters and their risk potential.

RESULTS

3531 tackles were recorded. Tackles in which the tackling player came from the side and stayed on her feet accounted for nearly half of all challenges for the ball in which body contact occurred. 2.7% of all tackles were classified as risk situations, with sliding-in tackles from behind and the side having the highest risk potential. Match referees sanctioned sliding-in tackles more often than other tackles (20% v 17%, respectively). Tackle parameters did not change in the duration of a match; however, there was an increase in the number of injury risk situations and foul plays towards the end of each half.

CONCLUSIONS

Match properties provide valuable information for a better understanding of injury situations in football. Staying on feet and jumping vertically tackle actions leading to injury were sanctioned significantly more times by the referee than those not leading to injury (p<0.001), but no such difference was seen for sliding-in tackles (previously reported to have the highest injury potential in women's football). Therefore, either the laws of the game are not adequate or match referees in women's football are not able to distinguish between sliding-in tackles leading to and those not leading to injury.

Causation of injuries in female football players in top-level tournaments

BACKGROUND

Analyses of tackle parameters in injury situations have provided valuable information regarding men's football. However, there are no similar data for women's football.

OBJECTIVE

To categorise the tackle mechanisms leading to injury in elite women's football.

STUDY DESIGN

Retrospective video analysis of injury situations.

METHODS

Events associated with all reported injuries during six women's top-level tournaments were analysed on video recordings for tackle parameters.

RESULTS

More than half of all injuries were due to tackles from the side (52%, 103/200), whereas tackles from behind were much less commonly involved in injury situations (11%, 21/200). One-footed (65%, 130/200) and upper body (21%, 42/200) tackle actions were most common. Sliding-in tackles leading to injury were the least likely to be sanctioned by match referees. Tackling players (45%, 90/200) were almost as likely to be injured as the tackled player (55%).

CONCLUSION

The present study found differences between injury mechanisms in women's football and previously published data on men's football. Further research, especially using video analysis, is needed for a better understanding of risk situations in football.

Consensus statement on injury definitions and data collection procedures for studies of injuries in rugby union

Wide variations in the definitions and methodologies used for studies of injuries in rugby union have created inconsistencies in reported data and made interstudy comparisons of results difficult. The International Rugby Board established a Rugby Injury Consensus Group (RICG) to agree on appropriate definitions and methodologies to standardize the recording of injuries and reporting of studies in rugby union. The RICG reviewed the consensus definitions and methodologies previously published for football (soccer) at a meeting in Dublin to assess their suitability for and application to rugby union. Following this meeting, iterative draft statements were prepared and circulated to members of the RICG for comment; a follow-up meeting was arranged in Dublin at which time all definitions and procedures were finalized. At this stage, all authors confirmed their agreement with the consensus statement. The agreed-on document was presented to and approved by the International Rugby Board Council. Agreement was reached on definitions for injury, recurrent injury, nonfatal catastrophic injury, and training and match exposures together with criteria for classifying injuries in terms of severity, location, type, diagnosis, and causation. The definitions and methodology presented in this consensus statement for rugby union are similar to those proposed for football. Adoption of the proposals presented in this consensus statement should ensure that more consistent and comparable results will be obtained from studies of injuries within rugby union.

Consensus statement on injury definitions and data collection procedures in studies of football (soccer) injuries

Variations in definitions and methodologies have created differences in the results and conclusions obtained from studies of football (soccer) injuries, making interstudy comparisons difficult. Therefore an Injury Consensus Group was established under the auspices of Fédération Internationale de Football Association Medical Assessment and Research Centre. A nominal group consensus model approach was used. A working document on definitions, methodology, and implementation was discussed by the group. Iterative draft statements were prepared and circulated to members of the group for comment before the final consensus statement was produced. Definitions of injury, recurrent injury, severity, and training and match exposures in football together with criteria for classifying injuries in terms of location, type, diagnosis, and causation are proposed. Proforma for recording players' baseline information, injuries, and training and match exposures are presented. Recommendations are made on how the incidence of match and training injuries should be reported and a checklist of issues and information that should be included in published reports of studies of football injuries is presented.

Consensus statement on injury definitions and data collection procedures in studies of football (soccer) injuries

Variations in definitions and methodologies have created differences in the results and conclusions obtained from studies of football injuries; this has made inter-study comparisons difficult. An Injury Consensus Group was established under the auspices of FIFA Medical Assessment and Research Centre. Using a nominal group consensus model approach, a working document that identified the key issues related to definitions, methodology and implementation was discussed by members of the group during a 2-day meeting. Following this meeting, iterative draft statements were prepared and circulated to members of the group for comment before the final consensus statement was produced. Definitions of injury, recurrent injury, severity and training and match exposures in football together with criteria for classifying injuries in terms of location, type, diagnosis and causation are proposed. Proforma for recording players' baseline information, injuries and training and match exposures are presented. Recommendations are made on how the incidence of match and training injuries should be reported and a checklist of issues and information that should be included in published reports of studies of football injuries is presented. The definitions and methodology proposed in the consensus statement will ensure that consistent and comparable results will be obtained from studies of football injuries.

Quantifying the functional rehabilitation of injured football players

OBJECTIVE

To determine whether quantified, auditable records of functional rehabilitation can be generated using subjective assessments of players' performance in fitness tests routinely used in professional football.

METHOD

Ten sequential test elements grouped into three phases (fitness, ball and match skills, match pace football) were used to monitor players' functional recovery from injury. Physiotherapists subjectively assessed players' performance in each test element using a six point subjective rating scale. Satisfactory performance in each element of the assessment programme added 10% to the injured player's recovery score. Daily recovery scores for injured players were recorded against the time spent in functional rehabilitation.

RESULTS

Rehabilitation data for 118 injuries sustained by 55 players over two seasons were recorded. The average time in functional rehabilitation depended on the time spent in pre-functional rehabilitation and the nature and location of injury. Benchmark functional rehabilitation curves (y = mln(x) + c) were developed for thigh (n = 15) and lower leg (n = 8) muscle strains and knee (n = 7) and ankle (n = 9) ligament sprains (R(2) = 0.95-0.98).

CONCLUSIONS

A structured, quantified rehabilitation programme based on routine fitness and skills exercises and a graded subjective assessment of performance provides an auditable record of a player's functional recovery from a range of lower limb injuries and a transparent exit point from rehabilitation. The proposed method provides a permanent record of the functional rehabilitation of players' injuries and evidence based data to support management's return to play decisions.

Terminal phosphate labeled nucleotides: synthesis, applications, and linker effect on incorporation by DNA polymerases

A number of terminal phosphate-labeled nucleotides with three or more phosphates and with varied length linkers attached between the terminal phosphate and the dye have been synthesized. These nucleotides have been tested as substrates for different DNA and RNA polymerases. We have also explored their utility in DNA sequencing, SNP analysis, nucleic acid amplification, quantitative PCR, and other biochemical assays.

Epidemiology of injuries in English professional rugby union: part 2 training Injuries

OBJECTIVES

To undertake a detailed epidemiological study of training injuries sustained by professional rugby union players in order to define their incidence, nature, severity, and causes.

METHODS

A two season prospective design was used to study training injuries associated with 502 rugby union players at 11 English Premiership clubs. Team clinicians reported all training injuries on a weekly basis and provided details of the location, diagnosis, severity, and mechanism of each injury. Training exposures for individual players were recorded on a weekly basis. Loss of time from training and match play was used as the definition of an injury.

RESULTS

The overall incidence of injury was 2.0 per 1000 player-hours, and each injury resulted on average in 24 days lost time. Recurrences, which accounted for 19% of injuries, were more severe (35 days) than new injuries (21 days). Twenty two per cent of all training occurred during the preseason but 34% of all injuries were sustained in this period. Hamstring, calf, hip flexor/quadriceps, and adductor muscle injuries were the most common for backs, whereas hamstring, lateral ankle ligament, and lumbar disc/nerve root injuries predominated for forwards. Lumbar disc/nerve root, shoulder dislocation/instability, and hamstring muscle injuries for forwards and hamstring muscle and anterior cruciate ligament injuries for backs caused the greatest number of days absence. Running was the predominant cause of injury for both forwards and backs, although the overall incidence and severity of injuries sustained during skills training were significantly greater than those sustained during conditioning training.

CONCLUSIONS

On average, a club will have 5% of their players unavailable for selection as a consequence of training injuries.

Epidemiology of injuries in English professional rugby union: part 1 match injuries

OBJECTIVES

To undertake a detailed, large scale epidemiological study of match injuries sustained by professional rugby union players in order to define their incidence, nature, severity, and causes.

METHODS

A two season prospective design was used to study match injuries associated with 546 rugby union players at 12 English Premiership clubs. Team clinicians reported all match injuries on a weekly basis and provided details of the location, diagnosis, severity, and mechanism of each injury. Match exposures for individual players were recorded on a weekly basis. Loss of time from training and match play was used as the definition of an injury.

RESULTS

The overall incidence of injury was 91 injuries/1000 player-hours, and each injury resulted on average in 18 days lost time. Recurrences, which accounted for 18% of injuries, were significantly more severe (27 days) than new injuries (16 days). Thigh haematomas were the most common injury for forwards and backs, but anterior cruciate ligament injuries for forwards and hamstring injuries for backs caused the greatest number of days absence. Contact mechanisms accounted for 72% of injuries, but foul play was only implicated in 6% of injuries. The ruck and maul elements of the game caused most injuries to forwards, and being tackled caused most injuries to backs. The hooker and outside centre were the playing positions at greatest risk of injury.

CONCLUSIONS

On average, a club will have 18% of their players unavailable for selection as a consequence of match injuries.

A six year prospective study of the incidence and causes of head and neck injuries in international football

OBJECTIVE

To identify those risk factors that have the greatest impact on the incidence of head and neck injuries in international football.

METHOD

A case-control study of players sustaining head and neck injuries during 20 FIFA tournaments (men and women) from 1998 to 2004. Video recordings of incidents were used to identify a range of parameters associated with the incidents. Team physicians provided medical reports describing the nature of each injury. chi2 tests (p< or =0.01) and 95% confidence intervals were used to assess differences in distribution and incidence of injury, respectively.

RESULTS

In total, 248 head and neck injuries were recorded of which 163 were identified and analysed on video sequences. The commonest injuries were contusions (53%), lacerations (20%), and concussions (11%). The incidence of all head and neck injuries was 12.5/1000 player hours (men 12.8, women 11.5) and 3.7 for lost-time injuries (men 3.5, women 4.1). The commonest causes of injury involved aerial challenges (55%) and the use of the upper extremity (33%) or head (30%). The unfair use of the upper extremity was significantly more likely to cause an injury than any other player action. Only one injury (a neck muscle strain) occurred as a result of heading the ball throughout the 20 tournaments equivalent to 0.05 injuries/1000 player hours.

CONCLUSIONS

Players' actions most likely to cause a head or neck injury were the use of the upper extremity or the head but in the majority of cases these challenges were deemed to be fair and within the laws of the game.

A prospective study of injuries and training amongst the England 2003 Rugby World Cup squad

OBJECTIVES

To assess the aetiology, incidence, severity, and causes of injuries to England rugby union players during preparation for and participation in the 2003 Rugby World Cup.

METHOD

A 63 week prospective design was employed to study the training practices and injuries of England rugby players. The team physician reported all training and match injuries and provided details of the location, diagnosis, severity, and mechanism of each injury. The team fitness coach reported details of the number and duration of training sessions and the time dedicated to rugby and conditioning training. Players' stature, body mass, and skinfolds were measured at the beginning and end of the study period.

RESULTS

The overall incidence of injury was 17 injuries/1000 h of exposure (match: 218 injuries/1000 h; training: 6.1 injuries/1000 h). The major locations of injuries were the lower (60%) and upper (17%) limbs and the most common diagnoses were muscle and tendon (50%) and joint (non-bone) and ligament (41%) injuries. The highest incidences of match injuries occurred whilst being tackled (50 injuries/1000 h) and in a ruck or maul (35 injuries/1000 h), whilst the greatest incidences of training injuries occurred during endurance running (24 injuries/1000 h) and contact activities (20 injuries/1000 h). Players' average body mass increased and skinfold measurement decreased significantly over the study period.

CONCLUSIONS

The incidence of match injuries at international level was found to be higher than previously reported. The tackle, ruck, and maul elements of match play and the endurance running and contact elements of training presented the highest risk of injury for all players.

Terminal phosphate-labeled nucleotides with improved substrate properties for homogeneous nucleic acid assays

Nucleotides with a dye attached to the terminal phosphate with four or more phosphates (tetra- or pentaphosphates) are superior substrates than the corresponding triphosphates for DNA and RNA polymerases. When fluorogenic dyes are directly attached to the terminal phosphate, they can be released by the action of polymerase and alkaline phosphatase. The released dye changes color and fluorescence properties. The fluorescent signal can also be amplified by using multiple labeled nucleotides to detect small amounts of template. We have explored the utility of these nucleotides in a variety of applications including homogeneous SNP detection methods, DNA sequencing, and quantitation of PCR and RCA.

An assessment of player error as an injury causation factor in international football

OBJECTIVE

To quantify the frequency of injury in football as a function of tackle parameters.

METHOD

Video recordings of 123 international matches in three Federation Internationale de Football Association tournaments were used to analyze tackle parameters, and team physicians provided reports of postmatch medical attention to players.

RESULTS

A total of 8572 tackles were assessed, of which 3464 (40.4%) were fouls. There were 299 incidents of on-pitch medical attention, of which 131 (44%) resulted from foul tackles, and 200 postmatch team physicians' reports, of which 96 (48%) resulted from foul tackles. The cases of on-pitch medical attention resulted in 76 (25%) postmatch physicians' reports, but 124 (62%) of the postmatch physicians' reports were not associated with on-pitch medical attention. Tackled players received 74% of the postmatch medical reports. Tackle types with the greatest probability of requiring medical attention were from the side in terms of tackle direction, jumping vertically in terms of tackle mode, and a clash of heads in terms of tackle action.

CONCLUSION

Human error on the part of players during the process of tackling and inadequacies in the laws of football and/or their application by match referees were equally responsible for the high levels of injury observed.

The influence of tackle parameters on the propensity for injury in international football

PURPOSE

To understand how tackling leads to injury in football, to develop a framework for classifying tackles, and to identify tackles with the greatest propensity to cause injury.

METHOD

Video recordings of 123 matches in three FIFA tournaments were used to identify tackling parameters. Team physicians prepared reports of postmatch medical attention to players.

RESULTS

Tackles from the side were twice as likely to require postmatch medical attention as tackles from behind. Injuries to the head/neck of tackled and tackling players and the torso of tackling players were more likely to receive on-pitch medical attention than other injuries. Injuries to the foot for tackled and tackling players and the lower leg and thigh for tackling players were less likely to receive on-pitch medical attention than other injuries. Tackles with the greatest propensity for causing injury involved clash of heads and two-footed tackles for tackled players and clash of heads, two-footed tackles, jumping vertically, and tackles from the side for tackling players.

CONCLUSION

The laws of football relating to tackling should be reviewed to provide greater protection from injury by reducing the overall level of risk and, in particular, by protecting players from tackles with the highest propensity for causing injury.

An assessment of football referees' decisions in incidents leading to player injuries

PURPOSE

To assess whether match injuries to footballers occurred as a result of players' noncompliance with the rules of the game, match referees could reliably identify the legality of incidents leading to injury, and the rules of football were adequate to protect players from injury.

METHODS

Video recordings of incidents leading to injury in 12 FIFA tournaments were used to identify parameters. Team physicians reported the details of match injuries. Two panels of FIFA referees reassessed the legality of incidents from these tournaments that resulted in injuries.

RESULTS

In total, 148 general injuries and 84 head/neck injuries were assessed. For the general injuries, the match referees identified 47% and the referees' panel identified 69% as fouls. For head injuries, the match referees identified 40% and the referees' panel identified 49% as fouls.

CONCLUSIONS

Decisions made on the legality of tackles leading to injury indicated that the current rules of football were adequate for the majority of tackle situations, although the reliability with which referees could identify fouls during some match conditions was low. For incidents leading to head/neck injuries, the match referees and the referees' panel both identified a smaller proportion of injury situations as fouls.

Negatively charged, dye labeled-dideoxynucleotides for "direct-load" DNA sequencing

A four-color set of negatively charged, single dye as well as energy transfer dye labeled-ddNTPs were synthesized and evaluated in combination with a novel polymerase in a "direct-load" DNA sequencing, obviating the laborious and time consuming post-reaction work-up.

Synthesis and energy transfer efficiency of FRET terminators derived from different linkers

A number of different energy transfer dye labeled-cassettes were synthesized using aminoacid based trifunctional linkers and coupled to the propargylamino-substituted dideoxynucleoside-5'-triphosphates (ddNTPs). These terminators were evaluated for their energy transfer efficiency and DNA sequencing potential using thermostable DNA polymerase.

Efficient incorporation of positively charged 2', 3'-dideoxynucleoside-5'-triphosphates by DNA polymerases and their application in 'direct-load' DNA sequencing

A series of charge-modified, dye-labeled 2', 3'-dideoxynucleoside-5'-triphosphates have been synthesized and evaluated as reagents for dye-terminator DNA sequencing. Unlike the commonly used dye-labeled terminators, these terminators possess a net positive charge and migrate in the opposite direction to dye-labeled Sanger fragments during electrophoresis. Post-sequencing reaction purification is not required to remove unreacted nucleotide or associated breakdown products prior to electrophoresis. Thus, DNA sequencing reaction mixtures can be loaded directly onto a separating medium such as a sequencing gel. The charge-modified nucleotides have also been shown to be more efficiently incorporated by a number of DNA polymerases than regular dye-labeled dideoxynucleotide terminators or indeed normal dideoxynucleoside-5'-triphosphates.

Evaluating the level of injury in English professional football using a risk based assessment process

OBJECTIVES

To show how epidemiological data can be presented and analysed in frequency based and risk based formats and how risk based information can simplify management decisions on injury prevention strategies in professional football.

METHODS

The club physiotherapists at four English professional football clubs prospectively recorded players' injuries over the period November 1994 to May 1997. The nature, location, and mechanism of each injury and the specific numbers of days that players were unavailable to train or play as a result of injuries were recorded. The rates of injury were evaluated on a risk matrix using the number of days and the estimated costs of absence as measures of injury consequences.

RESULTS

There was a significant difference in the time lost through injury as a function of injury severity (p<0.001). Slight and minor injuries accounted for 51% of all injuries but represented only 17% of the risk from injury, whereas major injuries accounted for only 12% of the number of injuries and 47% of the risk. Player to player contact injuries accounted for 39% of the risk of injury, and football specific activities accounted for 47% of the risk. The risks of acute injury in professional football were three orders of magnitude greater than those in the construction, manufacturing, and service sectors of industry.

CONCLUSIONS

The risks associated with minor, moderate, and major acute injuries and osteoarthritis in lower limb joints of professional footballers were found to be unacceptable when evaluated against work based risk criteria used by the Health and Safety Executive. All stakeholders within professional football were shown to have an important contribution to make in reducing the overall level of risk to players through the provision of risk prevention strategies.

Novel cyanine dye-labeled dideoxynucleoside triphosphates for DNA sequencing

Single color cyanine dye-labeled (Cy 5.0 and Cy 5.5) dideoxynucleoside-5'-triphosphates, or 'terminators', containing different spacer lengths were synthesized and evaluated for efficacy in DNA sequencing methods using a modified thermally stable DNA polymerase. The single color cyanine dye terminators were formulated into two separate sets of sequencing mixes, one for Cy 5.0 and the other for Cy 5.5, and evaluated on different automated sequencing platforms. Each set of mixes included two pyrimidine terminators with 17-atom linkers and two purine terminators with 10-atom linkers between the dye and the nucleotide. The two sets of cyanine dye-labeled terminators chosen for this cycle sequencing study produced improved band patterns with band uniformity similar to that obtained with dye-primer sequencing methods.

Synthesis and application of charge-modified dye-labeled dideoxynucleoside-5'-triphosphates to 'direct-load' DNA sequencing

A novel series of charge-modified, dye-labeled 2',3'-dideoxynucleoside-triphosphate terminators were synthesized and evaluated as reagents for DNA sequencing. These terminators possess an advantage over existing reagents in that no purification is required to remove unreacted nucleotide or associated breakdown products prior to electrophoretic separation of the sequencing fragments. This obviates the need for a time consuming post-reaction work up, allowing direct loading of DNA sequencing reaction mixtures onto a slab gel. Thermo Sequenase II DNA polymerase poorly incorporates the charge-modified terminators compared with regular dye-labeled terminators. However, extending the linker arm between dye and nucleotide and using a mutant form of a related DNA polymerase can in part mitigate the decrease in substrate efficiency. We also present evidence that these charge-modified terminators can relieve gel compression artefacts when used with dGTP in sequencing reactions.

TempliPhi, phi29 DNA polymerase based rolling circle amplification of templates for DNA sequencing

We have developed a novel, isothermal DNA amplification strategy that employs phi29 DNA polymerase and rolling circle amplification to generate high-quality templates for DNA sequencing reactions. The TempliPhi DNA amplification kits take advantage of the fact that cloned DNA is typically obtained in circular vectors, which are readily replicated in vitro using phi29 DNA polymerase by a rolling circle mechanism. This single subunit, proofreading DNA polymerase has excellent processivity and strand displacement properties for generation of multiple, tandem double-stranded copies of the circular DNA, generating as much as 10(7)-fold amplification. Large amounts of product (1-3 microg) can be obtained in as little as 4 hours. Input DNA can be as little as 0.01 ng of purified plasmid DNA, a single bacterial colony, or a 1 microL of a saturated overnight culture. Additionally, the presence of an associated proof reading function within the phi29 DNA polymerase ensures high-fidelity amplification. Once completed, the product DNA can be used directly in sequencing reactions. Additionally, the properties of phi29 DNA polymerase and its use in applications such as amplification ofhuman genomic DNA for genotyping studies is discussed.

Perceptions of retired professional soccer players about the provision of support services before and after retirement

OBJECTIVE

To determine the views of retired players about the provision of support services in English professional soccer before and after retirement and to assess the impact of career ending injury on these views.

METHOD

An anonymous self administered questionnaire was distributed to 500 former players registered with the English Professional Footballers' Association. The questions asked about personal details, current medical status, reasons for retirement, perceptions of the provision and quality of support services, and use of prophylactic treatments while injured.

RESULTS

Of the 500 questionnaires distributed, 185 (37%) were returned. The Professional Footballers' Association provided significantly (p<0.001) more help and advice to retired players on medical, financial, career, and educational matters than any other organisation. Although respondents showed some satisfaction with the provision of medical support, they were significantly (p<0.001) less satisfied with the provision of sports science (23%) and education/welfare (19%) support. Respondents who had retired through injury, however, were more dissatisfied with the provision of all services. Significantly (p<0.001) more respondents agreed with the view that injuries would reduce income earning potential, contribute to medical problems, and restrict the duration of their playing career. Respondents who had been medically diagnosed with osteoarthritis were significantly more likely, at some time, to have regularly received steroid injections while injured.

CONCLUSION

The results presented are consistent with other evidence that the provision of injury prevention and socioeconomic services at professional soccer clubs is inadequate. The soccer industry should therefore develop a long term strategy for managing the needs of players who are forced to retire through injury.

Propensity for osteoarthritis and lower limb joint pain in retired professional soccer players

OBJECTIVE

To quantify the prevalence of osteoarthritis and the severity of pain in the lower limb joints of players retired from English professional soccer.

METHOD

An anonymous self administered questionnaire was distributed to 500 former players registered with the English Professional Footballers' Association. The questionnaire was designed to gather information on personal details, physical activity loading patterns, history of lower limb joint injury, and current medical condition of the lower limb joints.

RESULTS

Of 500 questionnaires distributed, 185 (37%) were returned. Nearly half of the respondents (79: 47%) retired because of injury; 42% (33) were acute injuries and 58% (46) chronic injuries. Most of the acute injuries that led to early retirement were of the knee (15: 46%), followed by the ankle (7: 21%) and lower back (5: 15%). Most of the chronic injuries that led to early retirement were also of the knee (17: 37%), followed by the lower back (10: 22%) and the hip (4: 9%). Of all respondents, 32% (59) had been medically diagnosed with osteoarthritis in at least one of the lower limb joints. More respondents had been diagnosed with osteoarthritis in the knee joints than either the ankle or the hip joints. Significantly (p<0.001) more respondents reported pain in one lower extremity joint during one or more daily activities than those who did not (joint pain: 137, 80%; no joint pain: 35, 20%).

CONCLUSION

The risk for professional soccer players of osteoarthritis in at least one of the lower extremity joints is very high and significantly greater than for the general population. The results support the suggestion that professional soccer players should be provided with health surveillance during their playing career.

Analogs of guanine nucleoside triphosphates for sequencing applications

We have synthesized more than 30 different deoxyribonucleosides and triphosphates with modifications either in the base or the phosphate moiety as analogs of 2'-dGTP for DNA sequencing applications. All the modified nucleoside triphosphates were tested as substrates for DNA polymerases, including Sequenase T7 DNA polymerase or Thermo Sequenase DNA polymerase. Two of the analogs, 7-ethyl-7-deaza-dGTP and 7-hydroxymethyl-7-deaza-dGTP meet our requirements as better sequencing reagents.

Fluorescence resonance energy transfer dye nucleotide terminators: a new synthetic approach for high-throughout DNA sequencing

Fluorescence resonance energy transfer (FRET) based dye-nucleotide terminators (10-13) were designed, synthesized, and formulated with Thermo Sequenase II DNA polymerase into a robust kit for high throughput DNA sequencing. The key energy transfer (ET) rigid and linear linker (2), required for the syntheses of energy transfer cassettes (6-9) was synthesized via Heck coupling reaction on t-Boc-L-4-iodo-phenylalanine (1) with N-TFA-propargylamine.

A prospective epidemiological study of injuries in four English professional football clubs

OBJECTIVE

To define the causes of injuries to players in English professional football during competition and training.

METHOD

Lost time injuries to professional and youth players were prospectively recorded by physiotherapists at four English League clubs over the period 1994 to 1997. Data recorded included information related to the injury, date and place of occurrence, type of activity, and extrinsic Playing factors.

RESULTS

In all, 67% of all injuries occurred during competition. The overall injury frequency rate (IFR) was 8.5 injuries/1000 hours, with the IFR during competitions (27.7) being significantly (p < 0.01) higher than that during training (3.5). The IFRs for youth players were found to increase over the second half of the season, whereas they decreased for professional players. There were no significant differences in IFRs for professional and youth players during training. There were significantly (p < 0.01) injuries in competition in the 15 minute periods at the end of each half. Strains (41%), sprains (20%), and contusions (20%) represented the major types of injury. The thigh (23%), the ankle (17%), knee (14%), and lower leg (13%) represented the major locations of injury, with significantly (p < 0.01) more injuries to the dominant body side. Reinjury counted for 22% of all injuries. Only 12% of all injuries were caused by a breach of the rules of football, although player to player contact was involved in 41% of all injuries.

CONCLUSIONS

The overall level of injury to professional footballers has been showed to be around 1000 times higher times higher than for industrial occupations generally regarded as high risk. The high level of muscle strains, in particular, indicates possible weakness in fitness training programmes and use of warming up and cooling down procedures by clubs and the need for benchmarking players' levels of fitness and performance. Increasing levels of injury to youth players as a season progresses emphasizes the importance of controlling the exposure of young players to high levels of competition.

Uniform band intensities in fluorescent dye terminator sequencing

The use of Cyanine dye (Cy5 and Cy5.5) labeled dideoxy terminators with Thermo Sequenase DNA polymerase in DNA sequencing provides uniform band intensity, improved sequence read-length, and accuracy. It also greatly improves the ability to detect single base heterozygotes with dye-terminator sequencing method.

An examination of the frequency and severity of injuries and incidents at three levels of professional football

OBJECTIVE

To assess the risk of injury to professional footballers during European international and English Premier and First Division league matches.

METHODS

Videotaped recordings of 29, 49, and 93 matches from the 1996 European Championship, 1996/1997 English Premier season and 1994 to 1997 English First Division seasons respectively were analysed. During each match, several relevant variables, including the number of fouls, injuries, time of incident, player identity, and injury mechanism, were recorded.

RESULTS

Significantly more free kicks were awarded during international matches than during league matches; however, there were no significant differences between the numbers of free kicks awarded over the three First Division seasons assessed. Between 1.7 and 3.0% of fouls resulted in a player requiring treatment for injury, but only 15-28% of all injuries resulted from foul play. In all "non-foul" situations, in which injury resulted, at least 60% still involved player to player contact. No significant differences in injury frequency were observed between playing positions or match halves.

CONCLUSIONS

The results equate to a total of 808 players per season from the estimated 2600 players in the four English professional football leagues sustaining a match injury that caused them to miss at least one game. The large number of underlying "non-injury" incidents is identified as the reason for this level of injury rather than a higher ratio of "injury" to "non-injury" incidents in professional football compared with other occupations.

A preliminary assessment of professional footballers' awareness of injury prevention strategies

Players from five English professional football clubs completed a questionnaire containing 52 items relating to injury prevention practices and advice received on these issues. Responses were received from 55 players, which represents a mean response of 11 (4) and a response rate of 38 (14)% from each club (means (SD)). The main deficiencies in awareness of injury prevention strategies for players were identified as: use of shin pads during training, carbohydrate intake before and after training and after matches, cool downs after training and matches, and flexibility work. These deficiencies indicate a need for wider education of players in current injury prevention strategies.

Developing a health surveillance strategy for professional footballers in compliance with UK health and safety legislation

The need for health surveillance for professional footballers has been assessed against criteria specified in UK health and safety legislation. As footballers suffer from chronic injuries under normal playing conditions, professional football clubs have a requirement to implement health surveillance programmes to protect their players. A health surveillance programme, based on benchmarking a player's fitness and addressing the issues of pre-recruitment, pre-season, during-season, post-season, and rehabilitation assessment, is proposed.

Thermo Sequenase DNA polymerase and T. acidophilum pyrophosphatase: new thermostable enzymes for DNA sequencing

A combination of thermostable enzymes has been developed that produces higher quality cycle sequences. Thermo Sequenase DNA polymerase is a thermostable enzyme engineered to catalyze the incorporation of ddNTPs with an efficiency several thousandfold better than other thermostable DNA polymerases. Since the enzyme also catalyzes pyrophosphorolysis at dideoxy termini, a thermostable inorganic pyrophosphatase is needed to remove the pyrophosphate produced during sequencing reactions. Thermoplasma acidophilum inorganic pyrophosphatase (TAP) is thermostable and effective for converting pyrophosphate to orthophosphate. The use of the combination of Thermo Sequenase polymerase and TAP for cycle sequencing yields sequence data with uniform band intensities, allowing the determination of longer, more accurate sequence reads. Uniform band intensities also facilitate interpretation of sequence anomalies and the presence of mixed templates. Sequencing PCR products of DNA amplified from heterozygous diploid individuals results in signals of equal intensity from each allele.

DNA sequencing with [alpha-33P]-labeled ddNTP terminators: a new approach to DNA sequencing with Thermo Sequenase DNA polymerase

A new approach to DNA sequencing is described. The method is based on the use of [alpha-33P]-labeled dideoxyribonucleoside triphosphate terminators and Thermo Sequenase DNA polymerase in cycle sequencing. Thermo Sequenase DNA polymerase incorporates ddNTPs as efficiently as dNTPs, allowing the use of low concentrations of these nucleotides in DNA sequencing. Because only the properly terminated chains are labeled and visualized on autoradiography of the sequencing gels, the sequence results are free of background. The intensity of DNA bands generated are remarkably uniform, which makes reading of DNA sequences easy. By staggered loading of the sequencing gel (at 2-3 hour intervals), it is possible to sequence DNA at least 450 to 500 nucleotides. Exposure time for autoradiography with [alpha-33P] labels is much shorter than with [35S] and does not substantially compromise autoradiographic resolution. Data can be obtained after only 12 hours of exposure of an X-ray film. Moreover, cycle sequencing requires very small amounts of single- or double-stranded template. Consequently, it is even possible to generate sequence data from a single bacterial colony. The details of the protocol are presented in a stepwise manner, and some important parameters to be considered for sequencing with this method are discussed.