9 research outputs found
Mechanical considerations in fracture fixation
No full textBone’s capacity to repair following trauma is both unique and astounding. However, fractures sometimes fail to heal. Hence, the goal of fracture treatment is the restoration of bone’s structure, composition and function. Fracture fixation devices should provide a favourable mechanical and biological environment for healing to occur.\ud
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The use of internal fixation is increasing as these devices may be applied with less invasive techniques. Recent studies suggest however that, internal fixation devices may be overly stiff and suppresses callus formation. The degree of mechanical stability influences the healing outcome. This is determined by the stiffness of the fixation device and the degree of limb loading. This project aims to characterise the fixation stability of an internal plate fixation device and the influence of modifications to its configuration on implant stability. As there are no standardised methods for the determination of fixation stiffness, the first part of this project aims to compares different methodologies and determines the most appropriate method to characterise the stiffness of internal plate fixators.\ud
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The stiffness of a fixation device also influences the physiological loads experienced by the healing bone. Since bone adapts to this applied load by undergoing changes through a remodelling process, undesirable changes could occur during the period of treatment with an implant. The second part of this project aims to develop a methodology to quantify remodelling changes. This quantification is expected to aid our understanding of the changes in pattern due to implant related remodelling and on the factors driving the remodelling process. Knowledge gained in this project is useful to understand how the configuration of internal fixation devices can promote timely healing and prevent undesirable bone loss
Can the contra-lateral limb be used as a control with respect to analyses of bone remodelling?
No full textBone loss may result from remodelling initiated by implant stress protection. Quantifying remodelling requires bone density distributions which can be obtained from computed tomography scans. Pre-operative scans of large animals however are rarely possible. This study aimed to determine if the contra-lateral bone is a suitable control for the purpose of quantifying bone remodelling. CT scans of 8 pairs of ovine tibia were used to determine the likeness of left and right bones. The deviation between the outer surfaces of the bone pairs was used to quantify geometric similarity. The density differences were determined by dividing the bones into discrete volumes along the shaft of the tibia. Density differences were also determined for fractured and contra-lateral bone pairs to determine the magnitude of implant related remodelling. Left and right ovine tibiae were found to have a high degree of similarity with differences of less than 1.0 mm in the outer surface deviation and density difference of less than 5% in over 90% of the shaft region. The density differences (10–40%) as a result of implant related bone remodelling were greater than left-right differences. Therefore, for the purpose of quantifying bone remodelling in sheep, the contra-lateral tibia may be considered an alternative to a pre-operative control
Heat Transfer in MHD Mixed Convection Viscoelastic Fluid Flow over a Stretching Sheet Embedded in a Porous Medium with Viscous Dissipation and Non-uniform Heat Source/Sink
No full textAbstractA numerical model is developed to study the MHD mixed convective boundary layer viscoelastic fluid flow over a stretching sheet embedded in a porous medium in presence of viscous dissipation and non-uniform heat source have been investigated. The variation of porosity is assumed. The governing partial differential equations are converted into ordinary differential equations by applying suitable similarity transformations. The numerical solution of the problem is also obtained by the efficient Runge-Kutta-Fehlberg method with shooting technique. Here two types of different heating processes are considered namely, PST and PHF cases. The effect of various physical parameters such as Prandtl number, Eckert number, magnetic parameter, convection parameter and porous parameter which determine the temperature profiles are shown in several plots. Some important findings reported in this work reveals that the effect of viscous dissipation and non uniform heat source have significant impact in controlling the rate of heat transfer in the boundary layer region
Othering homelessness: how lone mothers manage housing insecurity in Prince Edward Island, Canada
No full textAbstract: Homelessness is a complex socio-economic and political problem that impacts health status and continues to challenge researchers and policy makers in Canada. Individuals and families who lack safe, affordable shelter are heterogeneous and represent almost every facet of society. Although living in poverty is a common denominator for those who experience homelessness, researchers report multiple contributors to housing insecurity including poor mental health, addiction, family violence, unemployment, and insufficient wages. Many of these contributors are understood to be consequences of individual circumstances rather than stemming from much broader socio-economic and political conditions.Research that has explored homelessness in Canada has predominantly been conducted in large urban areas. However, in Prince Edward Island, a province with a high percentage of rural residents, there is no research that has examined housing instability among any population, including lone parent mothers. This knowledge gap is a critical omission concerning women, especially for those who live in rural Canada as there is limited understanding of their daily challenges. The research question for this study was: How do lone parent mothers manage their lives while living homeless in Prince Edward Island? The methodology used was constructivist grounded theory. Similar to classic grounded theory, constructivist grounded theory aims to create a theoretical understanding of the basic social processes at play that are contributing to a social phenomenon, and how participants respond. The purpose of this doctoral study was to create a theoretical understanding of how and why homelessness among lone parent mothers in PEI is a problematic social-economic problem and how they managed in response to their circumstances.Fourteen lone mothers who had experienced homelessness were interviewed at a place and time of their choosing. Following ethics approval, data generation and analysis began immediately and continued in an iterative process until no further discernments were identified. By understanding the lone mothers’ behaviours in response to their socio-ecological circumstances, a social process became apparent which culminated in behaviours of othering the experience of homelessness. A theory titled Othering Homelessness: How Lone Mothers Manage Housing Insecurity in Prince Edward Island, Canada was created based on data analysis to explain this social process
A Tissue Engineering Solution for Segmental Defect Regeneration in Load-Bearing Long Bones
No full textThe reconstruction of large defects (>10 mm) in humans usually relies on bone graft transplantation. Limiting factors include availability of graft material, comorbidity, and insufficient integration into the damaged bone. We compare the gold standard autograft with biodegradable composite scaffolds consisting of medical-grade polycaprolactone and tricalcium phosphate combined with autologous bone marrow–derived mesenchymal stem cells (MSCs) or recombinant human bone morphogenetic protein 7 (rhBMP-7). Critical-sized defects in sheep—a model closely resembling human bone formation and structure—were treated with autograft, rhBMP-7, or MSCs. Bridging was observed within 3 months for both the autograft and the rhBMP-7 treatment. After 12 months, biomechanical analysis and microcomputed tomography imaging showed significantly greater bone formation and superior strength for the biomaterial scaffolds loaded with rhBMP-7 compared to the autograft. Axial bone distribution was greater at the interfaces. With rhBMP-7, at 3 months, the radial bone distribution within the scaffolds was homogeneous. At 12 months, however, significantly more bone was found in the scaffold architecture, indicating bone remodeling. Scaffolds alone or with MSC inclusion did not induce levels of bone formation comparable to those of the autograft and rhBMP-7 groups. Applied clinically, this approach using rhBMP-7 could overcome autograft-associated limitations
Author response: Restraint of presynaptic protein levels by Wnd/DLK signaling mediates synaptic defects associated with the kinesin-3 motor Unc-104
No full textThe survival of influenza A(H1N1)pdm09 virus on 4 household surfaces.
No full textWe investigated the survival of a pandemic strain of influenza A H1N1 on a variety of common household surfaces where multiple samples were taken from 4 types of common household fomite at 7 time points. Results showed that influenza A H1N1sw virus particles remained infectious for 48 hours on a wooden surface, for 24 hours on stainless steel and plastic surfaces, and for 8 hours on a cloth surface, although virus recovery from the cloth may have been suboptimal. Our results suggest that pandemic influenza A H1N1 can survive on common household fomites for extended periods of time, and that good hand hygiene and regular disinfection of commonly touched surfaces should be practiced during the influenza season to help reduce transmission
Impact of the international Nosocomial infection control consortium (INICC) multidimensional hand hygiene approach over 13 years in 51 cities of 19 limited-resource countries from Latin America, Asia, the Middle East, and Europe
No full textobjective. To assess the feasibility and effectiveness of the International Nosocomial Infection Control Consortium (INICC) multi- dimensional hand hygiene approach in 19 limited-resource countries and to analyze predictors of poor hand hygiene compliance. design. An observational, prospective, cohort, interventional, before-and-after study from April 1999 through December 2011. The study was divided into 2 periods: a 3-month baseline period and a 7-year follow-up period. setting. Ninety-nine intensive care unit (ICU) members of the INICC in Argentina, Brazil, China, Colombia, Costa Rica, Cuba, El Salvador, Greece, India, Lebanon, Lithuania, Macedonia, Mexico, Pakistan, Panama, Peru, Philippines, Poland, and Turkey. participants. Healthcare workers at 99 ICU members of the INICC. methods. A multidimensional hand hygiene approach was used, including (1) administrative support, (2) supplies availability, (3) education and training, (4) reminders in the workplace, (5) process surveillance, and (6) performance feedback. Observations were made for hand hygiene compliance in each ICU, during randomly selected 30-minute periods. results. A total of 149,727 opportunities for hand hygiene were observed. Overall hand hygiene compliance increased from 48.3percent to 71.4percent (P .01). Univariate analysis indicated that several variables were significantly associated with poor hand hygiene compliance, including males versus females (63percent vs 70percent; P .001), physicians versus nurses (62percent vs 72percent; P .001), and adult versus neonatal ICUs (67percent vs 81percent; P .001), among others. conclusions. Adherence to hand hygiene increased by 48percent with the INICC approach. Specific programs directed to improve hand hygiene for variables found to be predictors of poor hand hygiene compliance should be implemented. © 2013 by The Society for Healthcare Epidemiology of America. All rights reserved.Allegranzi B, 2010, INFECT CONT HOSP EP, V31, P133, DOI 10.1086-649796; Bischoff WE, 2000, ARCH INTERN MED, V160, P1017, DOI 10.1001-archinte.160.7.1017; Boyce John M, 2002, MMWR Recomm Rep, V51, P1; CONLY JM, 1989, AM J INFECT CONTROL, V17, P330, DOI 10.1016-0196-6553(89)90002-3; Deming W.E, 1986, OUT CRISIS; Dorsey ST, 1996, ACAD EMERG MED, V3, P360, DOI 10.1111-j.1553-2712.1996.tb03451.x; DUBBERT PM, 1990, INFECT CONT HOSP EP, V11, P191; GRAHAM M, 1990, AM J INFECT CONTROL, V18, P77, DOI 10.1016-0196-6553(90)90085-7; Guinan ME, 1997, AM J INFECT CONTROL, V25, P424, DOI 10.1016-S0196-6553(97)90092-4; HALEY RW, 1982, J INFECT DIS, V145, P875; Horan TC, 2008, AM J INFECT CONTROL, V36, P309, DOI 10.1016-j.ajic.2008.03.002; Jarvis WR, 1996, INFECT CONT HOSP EP, V17, P552; Lam BCC, 2004, PEDIATRICS, V114, pE565, DOI 10.1542-peds.2004-1107; Larson EL, 1997, AM J INFECT CONTROL, V25, P3, DOI 10.1016-S0196-6553(97)90046-8; Lipsett P A, 2001, Surg Infect (Larchmt), V2, P241, DOI 10.1089-109629601317202722; MAYER JA, 1986, INFECT CONT HOSP EP, V7, P259; Pittet D, 2009, INFECT CONT HOSP EP, V30, P611, DOI 10.1086-600379; PRESTON GA, 1981, AM J MED, V70, P641, DOI 10.1016-0002-9343(81)90588-X; Raju T N, 1999, J Perinatol, V19, P307, DOI 10.1038-sj.jp.7200155; Rosenthal VD, 2006, ANN INTERN MED, V145, P582; Rosenthal VD, 2004, INFECT CONT HOSP EP, V25, P47, DOI 10.1086-502291; Rosenthal VD, 2008, AM J INFECT CONTROL, V36, P627, DOI 10.1016-j.ajic.2008.03.003; Rosenthal VD, 2010, AM J INFECT CONTROL, V38, P95, DOI 10.1016-j.ajic.2009.12.004; Rosenthal VD, 2012, INFECT CONT HOSP EP, V33, P704, DOI 10.1086-666342; Rosenthal VD, 2012, INFECT CONT HOSP EP, V33, P696, DOI 10.1086-666341; Rosenthal VD, 2012, AM J INFECT CONTROL, V40, P497, DOI 10.1016-j.ajic.2011.08.005; Rosenthal VD, 2003, AM J INFECT CONTROL, V31, P85, DOI 10.1067-mic.2003.63; Rosenthal VD, 2010, INFECT CONT HOSP EP, V31, P1264, DOI 10.1086-657140; Rosenthal VD, 2012, INFECTION, V40, P517, DOI 10.1007-s15010-012-0278-x; Rosenthal V.D., 2008, AM J INFECT CONTROL, V36, P1; Rosenthal VD, 2012, AM J INFECT CONTROL, V40, P396, DOI 10.1016-j.ajic.2011.05.020; Rosenthal VD, 2012, CRIT CARE MED, V40, P3121, DOI 10.1097-CCM.0b013e3182657916; Rosenthal VD, 2006, AM J INFECT CONTROL, V34, P58, DOI 10.1016-j.ajic.2005.11.002; Rosenthal VD, 2003, AM J INFECT CONTROL, V31, P405, DOI 10.1067-mic.2003.52; Rosenthal VD, 2005, AM J INFECT CONTROL, V33, P392, DOI 10.1016-j.ajic.2004.08.009; Rosenthal VD, 2012, INFECTION, V40, P415, DOI 10.1007-s15010-012-0246-5; Safdar N, 2001, CURR INFECT DIS REP, V3, P487, DOI 10.1007-s11908-001-0085-5; SIMMONS B, 1990, INFECT CONT HOSP EP, V11, P589; Watanakunakorn C, 1998, INFECT CONT HOSP EP, V19, P858; WHO launches global patient safety challenge, 2005, INDIAN J MED SCI, V59, P46143
Impact of a multidimensional infection control strategy on catheter-associated urinary tract infection rates in the adult intensive care units of 15 developing countries: Findings of the International Nosocomial Infection Control Consortium (INICC)
No full textPurpose We aimed to evaluate the impact of a multidimensional infection control strategy for the reduction of the incidence of catheter-associated urinary tract infection (CAUTI) in patients hospitalized in adult intensive care units (AICUs) of hospitals which are members of the International Nosocomial Infection Control Consortium (INICC), from 40 cities of 15 developing countries: Argentina, Brazil, China, Colombia, Costa Rica, Cuba, India, Lebanon, Macedonia, Mexico, Morocco, Panama, Peru, Philippines, and Turkey. Methods We conducted a prospective before-after surveillance study of CAUTI rates on 56,429 patients hospitalized in 57 AICUs, during 360,667 bed-days. The study was divided into the baseline period (Phase 1) and the intervention period (Phase 2). In Phase 1, active surveillance was performed. In Phase 2, we implemented a multidimensional infection control approach that included: (1) a bundle of preventive measures, (2) education, (3) outcome surveillance, (4) process surveillance, (5) feedback of CAUTI rates, and (6) feedback of performance. The rates of CAUTI obtained in Phase 1 were compared with the rates obtained in Phase 2, after interventions were implemented. Results We recorded 253,122 urinary catheter (UC)-days: 30,390 in Phase 1 and 222,732 in Phase 2. In Phase 1, before the intervention, the CAUTI rate was 7.86 per 1,000 UC-days, and in Phase 2, after intervention, the rate of CAUTI decreased to 4.95 per 1,000 UC-days [relative risk (RR) 0.63 (95 percent confidence interval [CI] 0.55-0.72)], showing a 37 percent rate reduction. Conclusions Our study showed that the implementation of a multidimensional infection control strategy is associated with a significant reduction in the CAUTI rate in AICUs from developing countries. © Springer-Verlag 2012.Crouzet J, 2007, J HOSP INFECT, V67, P253, DOI 10.1016-j.jhin.2007.08.014; Edwards JR, 2009, AM J INFECT CONTROL, V37, P783, DOI 10.1016-j.ajic.2009.10.001; Higuera F, 2005, CRIT CARE MED, V33, P2022, DOI 10.1097-01.CCM.0000178190.89663.E5; Horan TC, 2008, AM J INFECT CONTROL, V36, P309, DOI 10.1016-j.ajic.2008.03.002; Leone M, 2003, INTENS CARE MED, V29, P1077, DOI 10.1007-s00134-003-1767-2; Lo Evelyn, 2008, Infect Control Hosp Epidemiol, V29 Suppl 1, pS41, DOI 10.1086-591066; Lynch P, 2007, BENNETT BRACHMANS HO, P255; Marra AR, 2011, AM J INFECT CONTROL, V39, P817, DOI 10.1016-j.ajic.2011.01.013; Rosenthal VD, 2006, ANN INTERN MED, V145, P582; Rosenthal VD, 2012, INFECTION; Rosenthal VD, 2004, INFECT CONT HOSP EP, V25, P47, DOI 10.1086-502291; Rosenthal Victor D, 2008, Am J Infect Control, V36, pe1, DOI 10.1016-j.ajic.2008.06.003; Rosenthal VD, 2012, INFECT CONT HOSP EP, V33, P704, DOI 10.1086-666342; Rosenthal VD, 2012, INFECT CONT HOSP EP, V33, P696, DOI 10.1086-666341; Rosenthal VD, 2011, AM J INFECT CONTROL; Rosenthal VD, 2010, INFECT CONT HOSP EP, V31, P1264, DOI 10.1086-657140; Rosenthal VD, 2012, AM J INFECT CONTROL, V40, P396, DOI 10.1016-j.ajic.2011.05.020; Rosenthal VD, 2011, J INFECTION, V62, P136, DOI 10.1016-j.jinf.2010.12.004; Rosenthal VD, 2011, INFECTION, V39, P439, DOI 10.1007-s15010-011-0136-2; Rosenthal VD, 2006, AM J INFECT CONTROL, V34, P58, DOI 10.1016-j.ajic.2005.11.002; Rosenthal VD, 2003, AM J INFECT CONTROL, V31, P405, DOI 10.1067-mic.2003.52; Rosenthal VD, 2005, AM J INFECT CONTROL, V33, P392, DOI 10.1016-j.ajic.2004.08.009; Salgado CD, 2003, PREVENTION CONTROL N, P297; Sax H, 2009, AM J INFECT CONTROL, V37, P827, DOI 10.1016-j.ajic.2009.07.003; Suwitra Ketut, 2004, Acta Med Indones, V36, P97; Talaat M, 2010, AM J INFECT CONTROL, V38, P222, DOI 10.1016-j.ajic.2009.06.011; Tambyah PA, 2002, INFECT CONT HOSP EP, V23, P27, DOI 10.1086-501964; Tao L, 2012, J CRIT CARE; Yildirim M, 2007, MYCOSES, V50, P189, DOI 10.1111-j.0933-7407.2006.01348.x; Zacharias Sumi, 2009, Indian J Crit Care Med, V13, P17, DOI 10.4103-0972-5229.5311017161
