This paper presents investigation of normal contact interaction between two bonded spherical particles with interface layer. For the evaluation of the interface of the finite size, the new analytical ...model involving sequentially connected spring was suggested. The bond having different radii and material properties was examined analytically and by applying the finite element method (FEM). Result shows, that introducing of the stiffness of interface layer reduces the total normal stiffness being confirmed by the FEM results.
Background: Researchers have investigated the performance of face mask removal tools for spine injury management in football but not
the effects of football equipment design.
Hypotheses: Various ...styles or designs of football helmet equipment (helmets, face masks, loop straps) affect face mask removal efficiency.
A cordless screwdriver performs more efficiently than do cutting tools.
Study Design: Controlled laboratory study.
Methods: Nineteen certified athletic trainers were randomly assigned to group 1 (cordless screwdriver and the FM Extractor) or group
2 (cordless screwdriver and the Trainerâs Angel). Subjects randomly performed face mask removal for 6 conditions composed
of helmet (3), face mask (3), and loop strap (5) combinations. Time, head movement, perceived difficulty, and success rates
were measured.
Results: Multiple significant differences were found in time, movement, and perceived difficulty between the 6 helmet equipment conditions.
The Shockblocker loop strap was consistently superior in all variables regardless of the tool used or the helmet it was attached
to. The cordless screwdriver created less movement (mean range from any one plane, 2.8°â13.3°), was faster (mean range, 42.1â68.8
seconds), and was less difficult (mean rating of perceived exertion range, 1.4â2.9) compared to cutting tools (ranges, 4.4°â18.4°
in any one plane, 71â174 seconds, rating of perceived exertion, 2.8â7.7). Trial failure was more common with cutting tools
than with the screwdriver.
Conclusion: Differences in football helmet equipment affect face mask removal. The cordless screwdriver is more efficient than the FM
Extractor and Trainerâs Angel.
Clinical Relevance: Professionals responsible for the care of football athletes must be knowledgeable in the types of equipment used and the
best option available for effective airway access.
Keywords:
cervical spine injury
emergency management
airway access
football injury
Patients with type 2 diabetes are at high risk of fatal and non-fatal myocardial infarction and stroke. There is indirect evidence that agonists of peroxisome proliferator-activated receptor γ (PPAR ...γ) could reduce macrovascular complications. Our aim, therefore, was to ascertain whether pioglitazone reduces macrovascular morbidity and mortality in high-risk patients with type 2 diabetes.
We did a prospective, randomised controlled trial in 5238 patients with type 2 diabetes who had evidence of macrovascular disease. We recruited patients from primary-care practices and hospitals. We assigned patients to oral pioglitazone titrated from 15 mg to 45 mg (n=2605) or matching placebo (n=2633), to be taken in addition to their glucose-lowering drugs and other medications. Our primary endpoint was the composite of all-cause mortality, non fatal myocardial infarction (including silent myocardial infarction), stroke, acute coronary syndrome, endovascular or surgical intervention in the coronary or leg arteries, and amputation above the ankle. Analysis was by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN NCT00174993.
Two patients were lost to follow-up, but were included in analyses. The average time of observation was 34·5 months. 514 of 2605 patients in the pioglitazone group and 572 of 2633 patients in the placebo group had at least one event in the primary composite endpoint (HR 0·90, 95% CI 0·80–1·02, p=0·095). The main secondary endpoint was the composite of all-cause mortality, non-fatal myocardial infarction, and stroke. 301 patients in the pioglitazone group and 358 in the placebo group reached this endpoint (0·84, 0·72–0·98, p=0·027). Overall safety and tolerability was good with no change in the safety profile of pioglitazone identified. 6% (149 of 2065) and 4% (108 of 2633) of those in the pioglitazone and placebo groups, respectively, were admitted to hospital with heart failure; mortality rates from heart failure did not differ between groups.
Pioglitazone reduces the composite of all-cause mortality, non-fatal myocardial infarction, and stroke in patients with type 2 diabetes who have a high risk of macrovascular events.
In this paper data about four types cast irons chemical composition, microstructure, static mechanical properties, durability and cyclic fracture toughness is given. Ultimate stress obtained using ...cylindrical specimens of diameters 8-14mm with circular notch are sigma (u)=403-692 MPa. Endurance limit values of notched specimens are sigma (0)=85-96 MPa. The performed analysis of breaks shows that heterogeneities and defects (voids) formation have an influence on static and cyclic fracture, because they change the crack front and shape of final fracture's zone. The values of cyclic fracture toughness obtained according to the shape of final fracture's zone are K(c)=10-26 MPa square root m. The obtained data allows deciding about the suitability of cast irons for structural elements production.
Most research on face mask removal has been performed on unused equipment.
To identify and compare factors that influence the condition of helmet components and their relationship to face mask ...removal.
A cross-sectional, retrospective study.
Five athletic equipment reconditioning/recertification facilities.
2584 helmets from 46 high school football teams representing 5 geographic regions.
Helmet characteristics (brand, model, hardware components) were recorded. Helmets were mounted and face mask removal was attempted using a cordless screwdriver. The 2004 season profiles and weather histories were obtained for each high school.
Success and failure (including reason) for removal of 4 screws from the face mask were noted. Failure rates among regions, teams, reconditioning year, and screw color (type) were compared. Weather histories were compared. We conducted a discriminant analysis to determine if weather variables, region, helmet brand and model, reconditioning year, and screw color could predict successful face mask removal. Metallurgic analysis of screw samples was performed.
All screws were successfully removed from 2165 (84%) helmets. At least 1 screw could not be removed from 419 (16%) helmets. Significant differences were found for mean screw failure per helmet among the 5 regions, with the Midwest having the lowest failure rate (0.08 +/- 0.38) and the Southern (0.33 +/- 0.72), the highest. Differences were found in screw failure rates among the 46 teams (F(1,45) = 9.4, P < .01). Helmets with the longest interval since last reconditioning (3 years) had the highest failure rate, 0.47 +/- 0.93. Differences in success rates were found among 4 screw types (chi(2) (1,4) = 647, P < .01), with silver screws having the lowest percentage of failures (3.4%). A discriminant analysis (Lambda = .932, chi(2) (14,n=2584) = 175.34, P < .001) revealed screw type to be the strongest predictor of successful removal.
Helmets with stainless steel or nickel-plated carbon steel screws reconditioned in the previous year had the most favorable combination of factors for successful screw removal. T-nut spinning at the side screw locations was the most common reason and location for failure.
The incidence of catastrophic cervical spine injury in sports is low compared with other injuries. However, cervical spine injuries necessitate delicate and precise management, often involving the ...combined efforts of a variety of health care providers. The outcome of a catastrophic cervical spine injury depends on the efficiency of this management process and timeliness of transfer to a controlled environment for diagnosis and treatment. The objective of the National Athletic Trainers' Association (NATA) position statement on the acute care of the cervical spine-injured athlete is to provide the certified athletic trainer, team physician, emergency responder, and other health care professionals with recommendations on how to best manage a catastrophic cervical spine injury in an athlete. Recommendations are based on current evidence pertaining to prevention strategies to reduce the incidence of cervical spine injuries in sport; emergency planning and preparation to increase management efficiency; maintaining or creating neutral alignment in the cervical spine; accessing and maintaining the airway; stabilizing and transferring the athlete with a suspected cervical spine injury; managing the athlete participating in an equipment-laden sport such as football, hockey, or lacrosse; and imaging considerations in the emergency department.
Ulnar neuropathy of the elbow Norkus, S A; Meyers, M C
Sports medicine (Auckland),
03/1994, Letnik:
17, Številka:
3
Journal Article
Recenzirano
Ulnar nerve entrapment is the second most common compressive neuropathy in the upper extremity because of its anatomy and superficial location. Major aetiological factors in the development of ulnar ...neuropathy of the elbow are compression, inherent anatomical structures, or lesions within the cubital tunnel. Extrinsic nerve compression may be elicited by acute or recurrent trauma. Nerve mobility may be impeded by congenital deformities. Ulnar nerve dysfunction has been associated with metabolic conditions, certain occupations and athletes involved in repetitive overhead activities. Ulnar nerve injuries may result in both motor and sensory abnormalities. Common symptoms include point tenderness, digital numbness and hand weakness. Evaluation of suspected neuropathy includes physical inspection for muscle atrophy, bony or muscle hypertrophy, deformities, digital clawing and a radiographic examination. Clinical techniques include the elbow flexion test, strength testing of hand intrinsics, flexor carpi ulnaris and digitorum profundus, and Tinel's sign. Sensory testing and McGowan's grading system may confirm the diagnosis and prognosis. Treatment options range from conservative (i.e. rest, splinting, nonsteroidal anti-inflammatory drugs, ice and abstinence) to radical surgical intervention (i.e. decompression, medical epicondylectomy and anterior transposition). In the throwing sport athlete, nerve involvement typically occurs along with other medical elbow problems.
OBJECTIVE: To quantify the amount of helmet movement, time for task completion, tool satisfaction, and overall efficiency for various face-mask removal tools during football helmet face-mask removal. ...DESIGN AND SETTING: Each subject performed one trial with the anvil pruner (AP), Face Mask Extractor (FME), PVC pipe cutter (PVC), and Trainer's Angel (TA). Each subject cut through 4 loop straps and removed the face mask while kneeling behind the athlete's head. SUBJECTS: Twenty-nine certified athletic trainers (age = 29.5 +/- 6.2 years, athletic training experience = 6.3 +/- 5.0 years). MEASUREMENTS: Time to complete the task was recorded. Total range of motion and total movement of the helmet were assessed using a 6-camera, 3-dimensional motion-capture system. Satisfaction scores were measured for each subject for each tool. Efficiency scores were calculated using time and total helmet-movement data. RESULTS: When using the FME, subjects were significantly faster than with all other tools (P <.05), and when using the AP and TA, they were significantly faster than with the PVC. No differences were noted between tools in either movement variable. Significant differences were noted for satisfaction (P <.05) for all comparisons except TA versus AP. Efficiency scores were FME, 11.6; AP, 14.3; TA, 14.5; and PVC, 22.9, with lower scores identifying increased efficiency. CONCLUSIONS: In general, subjects using the FME were superior in all variables except the movement variables. Future researchers should assess the removal task using specific protocols to determine whether the tools truly differ in terms of the movement created.
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