Mechanical characteristics of three staples commonly used in foot surgery

<p>Abstract</p> <p>Background</p> <p>Bone staples are an accepted method of fixation in foot surgery. They reduce operating time and trauma in surgical procedures. A variety of memory staples are available but their properties compared to standard staples are not known. We carried out a study comparing two popular types of memory staples and a standard stainless steel staple.</p> <p>Methods</p> <p>Standardized bone models of metatarsals made from Tufnol tubes were osteotomized and stabilised using one of three types of bone staples, two types of memory staple (Memory staple and heat-activated Memoclip) or a standard stainless steel staple (Richards). Constructs were loaded in bending and torsion on a material testing machine. The moment and torque to achieve 10 degree of bending or torsion and permanent angulation of the osteotomized bones were assessed.</p> <p>Results</p> <p>The Richards staple was found to provide a four times larger resistance to bending and torsion than the two memory staples. However, it was permanently deformed after bending. The Memory and Memoclip staples were equal in their stiffness. In addition, angulation of bones fixed with the Memoclip was elastic, preventing any permanent deformation.</p> <p>Conclusion</p> <p>The Richards staple was stiffer, although the permanent deformation of this staple is a disadvantage. Memoclip staples exhibit lower but adequate stiffnesss when compared to the standard Richards staple and are not permanently deformed after bending. The Memoclip staples were easier to handle. The results will enable surgeons to determine the optimal staple for foot and ankle procedures.</p

Fortnightly tides and subtidal motions in a choked inlet

This paper is not subject to U.S. copyright. The definitive version was published in Estuarine, Coastal and Shelf Science 150, Pt.B (2014): 325-331, doi:10.1016/j.ecss.2014.03.025.Amplitudes of semi-diurnal tidal fluctuations measured at an ocean inlet system decay nearly linearly by 87% between the ocean edge of the offshore ebb-tidal delta and the backbay. A monochromatic, dynamical model for a tidally choked inlet separately reproduces the evolution of the amplitudes and phases of the semi-diurnal and diurnal tidal constituents observed between the ocean and inland locations. However, the monochromatic model over-predicts the amplitude and under-predicts the lag of the lower-frequency subtidal and fortnightly motions observed in the backbay. A dimensional model that considers all tidal constituents simultaneously, balances the along-channel pressure gradient with quadratic bottom friction, and that includes a time-varying channel water depth, is used to show that that these model-data differences are associated with nonlinear interactions between the tidal constituents that are not included in non-dimensional, monochromatic models. In particular, numerical simulations suggest that the nonlinear interactions induced by quadratic bottom friction modify the amplitude and phase of the subtidal and fortnightly backbay response. This nonlinear effect on the low-frequency (subtidal and fortnightly) motions increases with increasing high-frequency (semi-diurnal) amplitude. The subtidal and fortnightly motions influence water exchange processes, and thus backbay temperature and salinity.We thank the Office of Naval Research (N0001411WX20962; N0001412WX20498) for funding

Let\u27s talk about antibiotics: A randomised trial of two interventions to reduce antibiotic misuse

BACKGROUND: Children with acute respiratory tract infections (ARTIs) receive ≈11.4 million unnecessary antibiotic prescriptions annually. A noted contributor is inadequate parent-clinician communication, however, efforts to reduce overprescribing have only indirectly targeted communication or been impractical. OBJECTIVES: Compare two feasible (higher vs lower intensity) interventions for enhancing parent-clinician communication on the rate of inappropriate antibiotic prescribing. DESIGN: Multisite, parallel group, cluster randomised comparative effectiveness trial. Data collected between March 2017 and March 2019. SETTING: Academic and private practice outpatient clinics. PARTICIPANTS: Clinicians (n=41, 85% of eligible approached) and 1599 parent-child dyads (ages 1-5 years with ARTI symptoms, 71% of eligible approached). INTERVENTIONS: All clinicians received 20 min ARTI diagnosis and treatment education. Higher intensity clinicians received an additional 50 min communication skills training. All parents viewed a 90 second antibiotic education video. MAIN OUTCOMES AND MEASURES: Inappropriate antibiotic treatment was assessed via blinded medical record review by study clinicians and a priori defined as prescriptions for the wrong diagnosis or use of the wrong agent. Secondary outcomes were revisits, adverse drug reactions (both assessed 2 weeks after the visit) and parent ratings of provider communication, shared decision-making and visit satisfaction (assessed at end of the visit on Likert-type scales). RESULTS: Most clinicians completed the study (n=38, 93%), were doctors (n=25, 66%), female (n=30, 78%) and averaged 8 years in practice. All parent-child dyad provided data for the main outcome (n=855 (54%) male, n=1043 (53%) CONCLUSIONS AND RELEVANCE: Rate of inappropriate prescribing was low in both arms. Clinician education coupled with parent education may be sufficient to yield low inappropriate antibiotic prescribing rates. The absence of a significant difference between groups indicates that communication principles previously thought to drive inappropriate prescribing may need to be re-examined or may not have as much of an impact in practices where prescribing has improved in recent years. TRIAL REGISTRATION NUMBER: NCT03037112

The law of trade disputes- common law and statutory

Includes bibliographical references

Stratified fronts in well-mixed estuaries

The occurrence of tidal intrusion fronts in a well-mixed estuary is demonstrated through both model simulation and field observation. Strong vertical mixing in well-mixed estuaries typically does not allow for development of stratification, which is a defining feature of tidal intrusion fronts. New methodology to compute a mutual realization surface of critical width and depth from model output is described that evaluates how the geometry of a basin releases tidal inflow from the hydraulic control of an inlet and the resulting front character. Force balance relationships of these features are evaluated in three dimensions for the first time. From this, Froude angle techniques are adapted to assess and predict how the geometry controls the behavior of the front after it is formed. Intrusion fronts observed in the field do not precisely conform to the conceptual model, but a modest field validation of Froude angle usage informs an axis rotation that results in agreement with established hydraulic theory. Frontogenetic mechanisms are proposed from the observations to describe the importance of morphological complexity and water mass segregation to the occurrence of bathymetrically induced confluent subduction in a well-mixed estuary.http://archive.org/details/stratifiedfronts1094537742Commander, United States NavyApproved for public release; distribution is unlimited

Bedform evolution and sediment transport under breaking waves

Observations of the temporal evolution of ripples are analyzed in terms of geometry, migration, crest orientation, and their predicted geometry by models using wave orbital velocities. Two weeks of bedform data were obtained in the surf zone during the RIPEX/SBE in April, 2001. Bed sediment consists of medium- to coarse-grained sand (D50=0.43mm). Models capture temporal trends in ripple geometry, but regression analyses show that they do not handle the range in forcing characteristics and geometries in the surf zone well. Transport models of bedload and total load formulated under uni-directional flows qualitatively capture the temporal evolution of observed transport by ripples, suggesting that under low to moderate forcing, bed load and suspended load occur mostly within the bed-following bottom boundary layer, andare measurable by ripple migration alone. Models predict large transport rates when flat beds were observed, so that at higher forcing ripples cannot be used to measure total sediment transport. Using a two-dimensional probability density function (PDF) of vector displacement peaks, a new ripple analysis model is proposed, incorporating a hierarchy of forcing complexity that includes such physical processes as directional spreading, axis rotation, orbital asymmetry, superimposed currents and infragravity wave velocities. The two-dimensional PDF's are compared with concurrent three-dimensional bed maps and are found to assist in describing ripple sizes, types, orientations, and migration velocities.http://archive.org/details/bedformevolution109451049Lieutenant, United States NavyApproved for public release; distribution is unlimited