Cleopatra : Song

https://digitalcommons.library.umaine.edu/mmb-vp/3058/thumbnail.jp

Quantification of Head Acceleration Events in Rugby League: An Instrumented Mouthguard and Video Analysis Pilot Study

Instrumented mouthguards (iMG) were used to collect head acceleration events (HAE) in men’s professional rugby league matches. Peak linear acceleration (PLA), peak angular acceleration (PAA) and peak change in angular velocity (∆PAV) were collected using custom-fit iMG set with a 5 g single iMG-axis recording threshold. iMG were fitted to ten male Super League players for thirty-one player matches. Video analysis was conducted on HAE to identify the contact event; impacted player; tackle stage and head loading type. A total of 1622 video-verified HAE were recorded. Approximately three-quarters of HAE (75.7%) occurred below 10 g. Most (98.2%) HAE occurred during tackles (59.3% to tackler; 40.7% to ball carrier) and the initial collision stage of the tackle (43.9%). The initial collision stage resulted in significantly greater PAA and ∆PAV than secondary contact and play the ball tackle stages (p &lt; 0.001). Indirect HAE accounted for 29.8% of HAE and resulted in significantly greater ∆PAV (p &lt; 0.001) than direct HAE, but significantly lower PLA (p &lt; 0.001). Almost all HAE were sustained in the tackle, with the majority occurring during the initial collision stage, making it an area of focus for the development of player protection strategies for both ball carriers and tacklers. League-wide and community-level implementation of iMG could enable a greater understanding of head acceleration exposure between playing positions, cohorts, and levels of play.</p

Quantification of Head Acceleration Events in Rugby League: An Instrumented Mouthguard and Video Analysis Pilot Study

Instrumented mouthguards (iMG) were used to collect head acceleration events (HAE) in men's professional rugby league matches. Peak linear acceleration (PLA), peak angular acceleration (PAA) and peak change in angular velocity (ΔPAV) were collected using custom-fit iMG set with a 5 g single iMG-axis recording threshold. iMG were fitted to ten male Super League players for thirty-one player matches. Video analysis was conducted on HAE to identify the contact event; impacted player; tackle stage and head loading type. A total of 1622 video-verified HAE were recorded. Approximately three-quarters of HAE (75.7%) occurred below 10 g. Most (98.2%) HAE occurred during tackles (59.3% to tackler; 40.7% to ball carrier) and the initial collision stage of the tackle (43.9%). The initial collision stage resulted in significantly greater PAA and ΔPAV than secondary contact and play the ball tackle stages (p < 0.001). Indirect HAE accounted for 29.8% of HAE and resulted in significantly greater ΔPAV (p < 0.001) than direct HAE, but significantly lower PLA (p < 0.001). Almost all HAE were sustained in the tackle, with the majority occurring during the initial collision stage, making it an area of focus for the development of player protection strategies for both ball carriers and tacklers. League-wide and community-level implementation of iMG could enable a greater understanding of head acceleration exposure between playing positions, cohorts, and levels of play

Atenolol versus losartan in children and young adults with Marfan's syndrome

BACKGROUND : Aortic-root dissection is the leading cause of death in Marfan's syndrome. Studies suggest that with regard to slowing aortic-root enlargement, losartan may be more effective than beta-blockers, the current standard therapy in most centers. METHODS : We conducted a randomized trial comparing losartan with atenolol in children and young adults with Marfan's syndrome. The primary outcome was the rate of aortic-root enlargement, expressed as the change in the maximum aortic-root-diameter z score indexed to body-surface area (hereafter, aortic-root z score) over a 3-year period. Secondary outcomes included the rate of change in the absolute diameter of the aortic root; the rate of change in aortic regurgitation; the time to aortic dissection, aortic-root surgery, or death; somatic growth; and the incidence of adverse events. RESULTS : From January 2007 through February 2011, a total of 21 clinical centers enrolled 608 participants, 6 months to 25 years of age (mean [+/- SD] age, 11.5 +/- 6.5 years in the atenolol group and 11.0 +/- 6.2 years in the losartan group), who had an aorticroot z score greater than 3.0. The baseline-adjusted rate of change (+/- SE) in the aortic-root z score did not differ significantly between the atenolol group and the losartan group (-0.139 +/- 0.013 and -0.107 +/- 0.013 standard-deviation units per year, respectively; P = 0.08). Both slopes were significantly less than zero, indicating a decrease in the degree of aortic-root dilatation relative to body-surface area with either treatment. The 3-year rates of aortic-root surgery, aortic dissection, death, and a composite of these events did not differ significantly between the two treatment groups. CONCLUSIONS : Among children and young adults with Marfan's syndrome who were randomly assigned to losartan or atenolol, we found no significant difference in the rate of aorticroot dilatation between the two treatment groups over a 3-year period

Ready for impact? A validity and feasibility study of instrumented mouthguards (iMGs)

Objectives Assess the validity and feasibility of current instrumented mouthguards (iMGs) and associated systems. Methods Phase I; four iMG systems (Biocore-Football Research Inc (FRI), HitIQ, ORB, Prevent) were compared against dummy headform laboratory criterion standards (25, 50, 75, 100 g). Phase II; four iMG systems were evaluated for on-field validity of iMG-triggered events against video-verification to determine true-positives, false-positives and false-negatives (20±9 player matches per iMG). Phase III; four iMG systems were evaluated by 18 rugby players, for perceptions of fit, comfort and function. Phase IV; three iMG systems (Biocore-FRI, HitIQ, Prevent) were evaluated for practical feasibility (System Usability Scale (SUS)) by four practitioners. Results Phase I; total concordance correlation coefficients were 0.986, 0.965, 0.525 and 0.984 for Biocore-FRI, HitIQ, ORB and Prevent. Phase II; different on-field kinematics were observed between iMGs. Positive predictive values were 0.98, 0.90, 0.53 and 0.94 for Biocore-FRI, HitIQ, ORB and Prevent. Sensitivity values were 0.51, 0.40, 0.71 and 0.75 for Biocore-FRI, HitIQ, ORB and Prevent. Phase III; player perceptions of fit, comfort and function were 77%, 6/10, 55% for Biocore-FRI, 88%, 8/10, 61% for HitIQ, 65%, 5/10, 43% for ORB and 85%, 8/10, 67% for Prevent. Phase IV; SUS (preparation-management) was 51.3-50.6/100, 71.3-78.8/100 and 83.8-80.0/100 for Biocore-FRI, HitIQ and Prevent. Conclusion This study shows differences between current iMG systems exist. Sporting organisations can use these findings when evaluating which iMG system is most appropriate to monitor head acceleration events in athletes, supporting player welfare initiatives related to concussion and head acceleration exposure.</p

Fibrin glue for pilonidal sinus disease

Background Pilonidal sinus disease is a common condition that mainly affects young adults. This condition can cause significant pain and impairment of normal activities. No consensus currently exists on the optimum treatment for pilonidal sinus and current therapies have various advantages and disadvantages. Fibrin glue has emerged as a potential treatment as both monotherapy and an adjunct to surgery. Objectives To assess the effects of fibrin glue alone or in combination with surgery compared with surgery alone in the treatment of pilonidal sinus disease. Search methods In December 2016 we searched: the Cochrane Wounds Specialised Register; CENTRAL; MEDLINE; Embase and CINAHL Plus. We also searched clinical trials registries and conference proceedings for ongoing and unpublished studies and scanned reference lists to identify additional studies. There were no restrictions with respect to language, date of publication or study setting. Selection criteria We included randomised controlled trials (RCTs) only. We included studies involving participants of all ages and studies conducted in any setting. We considered studies involving people with both new and recurrent pilonidal sinus. We included studies which evaluated fibrin glue monotherapy or as an adjunct to surgery. Data collection and analysis Two study authors independently extracted data and assessed risk of bias. We used standard methods expected by Cochrane. Main results We included four RCTs with 253 participants, all were at risk of bias. One unpublished study evaluated fibrin glue monotherapy compared with Bascom's procedure, two studies evaluated fibrin glue as an adjunct to Limberg flap and one study evaluated fibrin glue as an adjunct to Karydakis flap. For fibrin glue monotherapy compared with Bascom's procedure, there were no data available for the primary outcomes of time to healing and adverse events. There was low-quality evidence of less pain on day one after the procedure with fibrin glue monotherapy compared with Bascom's procedure (mean difference (MD) -2.50, 95% confidence interval (CI) -4.03 to -0.97) (evidence downgraded twice for risk of performance and detection bias). Fibrin glue may reduce the time taken to return to normal activities compared with Bascom's procedure (mean time 42 days with surgery and 7 days with glue, MD -34.80 days, 95% CI -66.82 days to -2.78 days) (very low-quality evidence, downgraded as above and for imprecision). Fibrin glue as an adjunct to the Limberg flap may reduce the healing time from 22 to 8 days compared with the Limberg flap alone (MD -13.95 days, 95% CI -16.76 days to -11.14 days) (very low-quality evidence, downgraded twice for risk of selection, performance and detection bias and imprecision). It is uncertain whether use of fibrin glue affects the incidence of postoperative seroma (an adverse event) (risk ratio (RR) 0.27, 95% CI 0.05 to 1.61; very low-quality evidence, downgraded twice for risk of selection, performance and detection bias and imprecision). There was low-quality evidence that fibrin glue, as an adjunct to Limberg flap, may reduce postoperative pain (median 2 versus 4; P < 0.001) and time to return to normal activities (median 8 days versus 17 days; P < 0.001). The addition of fibrin glue to the Limberg flap may reduce the length of hospital stay (MD -1.69 days, 95% CI -2.08 days to -1.29 days) (very low-quality evidence, downgraded twice for risk of selection, performance and detection bias and for unexplained heterogeneity). A single RCT evaluating fibrin glue as an adjunct to the Karydakis flap did not report data for the primary outcome of time to healing. It is uncertain whether fibrin glue with the Karydakis flap affects the incidence of postoperative seroma (adverse event) (RR 3.00, 95% CI 0.67 to 13.46) (very low-quality evidence, downgraded twice for risk of selection, performance and detection bias and for imprecision). Fibrin glue as an adjunct to Karydakis flap may reduce length of stay but this is highly uncertain (mean 2 days versus 3.7 days; P < 0.001, low-quality evidence downgraded twice for risk of selection, performance and detection bias). Authors' conclusions Current evidence is uncertain regarding any benefits associated with fibrin glue either as monotherapy or as an adjunct to surgery for people with pilonidal sinus disease. We identified only four RCTs and each was small and at risk of bias resulting in very low-quality evidence for the primary outcomes of time to healing and adverse events. Future studies should enrol many more participants, ensure adequate randomisation and blinding, whilst measuring clinically relevant outcomes

Development of a biomimetic collagen-hydroxyapatite scaffold for bone tissue engineering using a SBF immersion technique.

The objective of this study was to develop a biomimetic, highly porous collagen-hydroxyapatite (HA) composite scaffold for bone tissue engineering (TE), combining the biological performance and the high porosity of a collagen scaffold with the high mechanical stiffness of a HA scaffold. Pure collagen scaffolds were produced using a lyophilization process and immersed in simulated body fluid (SBF) to provide a biomimetic coating. Pure collagen scaffolds served as a control. The mechanical, material, and structural properties of the scaffolds were analyzed and the biological performance of the scaffolds was evaluated by monitoring the cellular metabolic activity and cell number at 1, 2, and 7 days post seeding. The SBF-treated scaffolds exhibited a significantly increased stiffness compared to the pure collagen group (4-fold increase), while a highly interconnected structure (95%) was retained. FTIR indicated that the SBF coating exhibited similar characteristics to pure HA. Micro-CT showed a homogeneous distribution of HA. Scanning electron microscopy also indicated a mineralization of the collagen combined with a precipitation of HA onto the collagen. The excellent biological performance of the collagen scaffolds was maintained in the collagen-HA scaffolds as demonstrated from cellular metabolic activity and total cell number. This investigation has successfully developed a biomimetic collagen-HA composite scaffold. An increase in the mechanical properties combined with an excellent biological performance in vitro was observed, indicating the high potential of the scaffold for bone TE

Permeability of rapid prototyped artificial bone scaffold structures

In this work, various three-dimensional (3D) scaffolds were produced via micro-stereolithography (µ-SLA) and 3D printing (3DP) techniques. This work demonstrates the advantages and disadvantages of these two different rapid prototyping methods for production of bone scaffolds. Compared to 3DP, SLA provides for smaller feature production with better dimensional resolution and accuracy. The permeability of these structures was evaluated experimentally and via numerical simulation utilizing a newly derived Kozeny–Carman based equation for intrinsic permeability. Both experimental and simulation studies took account of porosity percentage, pore size, and pore geometry. Porosity content was varied from 30% to 70%, pore size from 0.34 mm to 3 mm, and pore geometries of cubic and hexagonal closed packed were examined. Two different fluid viscosity levels of 1 mPa·s and 3.6 mPa·s were used. The experimental and theoretical results indicated that permeability increased when larger pore size, increased fluid viscosity, and higher percentage porosity were utilized, with highest to lowest degree of significance following the same order. Higher viscosity was found to result in permeabilities 2.2 to 3.3 times higher than for water. This latter result was found to be independent of pore morphology type. As well as demonstrating method for determining design parameters most beneficial for scaffold structure design, the results also illustrate how the variations in patient's blood viscosity can be extremely important in allowing for permeability through the bone and scaffold structures