Development of inspection systems for estimating the structural integrity of trees

Urban tree managers are charged with the responsibility of managing large tree populations while securing a safe environment. A conflict exists between the presence of urban trees and the potential hazards these trees can be to buildings, vehicles, and inhabitants. Determining the structural stability of urban trees for the purpose of maintaining public safety is a chief function of urban forestry. Various conceptual frameworks, systematised routines, and documentation tools are available to aid managers with tree evaluations and risk assessments. This report maps the historical development of modern structural risk assessment's start in conservation area management and its evolution, and application, into the urban arena. The report finds that the concept of the hazard tree exists only when there is the presence of valuated objects within the tree's area of influence. Thus, urban forestry, with the ubiquitous presence valuated objects such as pedestrians, vehicles, and buildings, has forced risk assessment, and management, to become an occupational responsibility for urban foresters. Events of structural failure resulting in injury and death are statistically low; however the frequency of structural failures increases during extreme meteorological events such as wind, ice, or snow storms. Numerical assessment systems were introduced as a tool for rating individual tree's structural status for the purpose of estimating the risk for failure while standardising evaluation techniques. These same systems are also used to regulating tree populations and validate pre-emptive management. This report samples four currently practiced tree risk assessment models with accompanying pro forma (protocol) documentation aids. Three systematic identification methods used to organise tree inventories for risk assessments are also examined. The following systems are presented and accompanied by short analyses pertaining to their area of application: 1) International Society of Arboriculture: A Photographic Guide to the Evaluation of Hazard Trees in Urban Areas (Mathney & Clark 1991) 2) The USDA Forest Service Community Tree Risk Rating System: 7-Step Program (Pokorny 2003) 3) Tree Hazard Rating, Evaluation And Treatment System (THREATS): A method for identifying, recording & managing hazards from trees (Forbes-Laird 2006) 4) Quantified Tree Risk Assessment (Ellison 2005) The report's discussion applies these assessment systems to a hypothetical situation involving a mature treed avenue along a major city road where the trunk diameter at chest height (DBH) exceeds 75cm. Each calculation's result and consequence is discussed to demonstrate the differences between the systems. The variations between the four assessment systems show that alternative models are available which inflate or deflate mature tree hazard rating. ---------------------------------------- Urbana trädförvaltare är ansvariga för skötsel och underhåll av stora trädbestånd, de är även förpliktigade att säkra stadens utemiljö. En konflikt existerar emellan stadens behov av träd och de möjliga faror de kan utgöra för fastigheter, fordon och invånare som kan uppträda när deras tillstånd försämras. Att fastställa trädens strukturella skick är ett grundläggande uppdrag för trädförvaltaren. Olika ramverk finns, med arbetsrutiner och dokumentationsredskap, för att hjälpa förvaltare med trädbesiktningar och riskbedömningar. Denna rapport har undersökt de ursprungliga källorna till moderna strukturella riskbedömningar av stadsträd och ett urval av aktuella modeller, system och medföljande dokumentationsunderlag som erbjuds. Rapporten visar på att begreppet riskträd endast uppstår när det finns ett samband mellan de föremål och deras värde, som finns inom trädets påverkningsområde. Denna realitet har gjort att trädförvaltning också bör inkludera kompetens att hantera objektiva riskhanterningsmetoder på grund av ständig närvaro av invånare, fordon och fastigheter. Statistik visar att allvarliga incidenter relaterade till bristfälliga träd är låg, dock ökar svåra olyckor när stormar av olika slag inträffar. I rapporten beskrivs tre systematiska identifikationsmetoders användbarhet gällande inventering och riskbedömning av stadsträd. Implementering av numeriska bedömningssystem kan fungera som ett standardiserat förvaltningsverktyg för att bedöma och värdera enskilda träds tillstånd med anledning att uppskatta bristfälligheter, reglera urbana trädbestånds tillstånd samt att stödja förebyggande åtgärder. Fyra utvalda bedömningssystem presenteras vilka visar att alternativa modeller är tillgängliga för att öka eller minska riskbedömningsvärdet av enskilda träd. De följande fyra bedömningssystem för besiktning av träds strukturella hållbarhet presenteras med korta analyser av deras tillämpningsområde: 1) International Society of Arboriculture: A Photographic Guide to the Evaluation of Hazard Trees in Urban Areas (Mathney & Clark 1991) 2) The USDA Forest Service Community Tree Risk Rating System: 7-Step Program (Pokorny 2003) 3) Tree Hazard Rating, Evaluation And Treatment System (THREATS): A method for identifying, recording & managing hazards from trees (Forbes-Laird 2006) 4) Quantified Tree Risk Assessment (Ellison 2005) I diskussionen appliceras samtliga bedömningssystem i en hypotetisk situation med en äldre allé längs en högtrafikerad väg där stammarnas diameter är över 75cm. Uträkningens resultat och konsekvenser diskuteras, för att demonstrera samtliga bedömningssystems inbyggda egenskaper.Urbana trädförvaltare är ansvariga för skötsel och underhåll av stora trädbestånd, de är även förpliktigade att säkra stadens utemiljö. En konflikt existerar emellan stadens behov av träd och de möjliga faror de kan utgöra för fastigheter, fordon och invånare som kan uppträda när deras tillstånd försämras. Att fastställa trädens strukturella skick är ett grundläggande uppdrag för trädförvaltaren. Olika ramverk finns, med arbetsrutiner och dokumentationsredskap, för att hjälpa förvaltare med trädbesiktningar och riskbedömningar. Denna rapport har undersökt de ursprungliga källorna till moderna strukturella riskbedömningar av stadsträd och ett urval av aktuella modeller, system och medföljande dokumentationsunderlag som erbjuds. Rapporten visar på att begreppet riskträd endast uppstår när det finns ett samband mellan de föremål och deras värde, som finns inom trädets påverkningsområde. Denna realitet har gjort att trädförvaltning också bör inkludera kompetens att hantera objektiva riskhanterningsmetoder på grund av ständig närvaro av invånare, fordon och fastigheter. Statistik visar att allvarliga incidenter relaterade till bristfälliga träd är låg, dock ökar svåra olyckor när stormar av olika slag inträffar. I rapporten beskrivs tre systematiska identifikationsmetoders användbarhet gällande inventering och riskbedömning av stadsträd. Implementering av numeriska bedömningssystem kan fungera som ett standardiserat förvaltningsverktyg för att bedöma och värdera enskilda träds tillstånd med anledning att uppskatta bristfälligheter, reglera urbana trädbestånds tillstånd samt att stödja förebyggande åtgärder. Fyra utvalda bedömningssystem presenteras vilka visar att alternativa modeller är tillgängliga för att öka eller minska riskbedömningsvärdet av enskilda träd. De följande fyra bedömningssystem för besiktning av träds strukturella hållbarhet presenteras med korta analyser av deras tillämpningsområde: 1) International Society of Arboriculture: A Photographic Guide to the Evaluation of Hazard Trees in Urban Areas (Mathney & Clark 1991) 2) The USDA Forest Service Community Tree Risk Rating System: 7-Step Program (Pokorny 2003) 3) Tree Hazard Rating, Evaluation And Treatment System (THREATS): A method for identifying, recording & managing hazards from trees (Forbes-Laird 2006) 4) Quantified Tree Risk Assessment (Ellison 2005) I diskussionen appliceras samtliga bedömningssystem i en hypotetisk situation med en äldre allé längs en högtrafikerad väg där stammarnas diameter är över 75cm. Uträkningens resultat och konsekvenser diskuteras, för att demonstrera samtliga bedömningssystems inbyggda egenskaper

Gender relations and couple negotiations of British men's food practice changes after prostate cancer.

Nutrition plays an important role in the health of men diagnosed with prostate cancer and dietary interventions can therefore be a significant part of prostate cancer survivorship supportive care. Family food provision, however, involves complex social interactions, which shape how men engage with their diets and dietary interventions. The role that gender plays in shaping prostate cancer couples' food practices and men's diets after a prostate cancer diagnosis is thought to be important but is little understood. This study explored couples' accounts of nutrition information seeking and diet change to gain a better understanding of how gender relations shaped men's food practices after prostate cancer diagnosis. Qualitative health interviews with men and their partners were conducted and analysed using interpretive descriptive methods. Findings demonstrated how couples navigated food change journeys that involved seeking information, deciding what changes were warranted and implementing and regulating diet changes. Two overarching themes that illustrated couples' food negotiations were called 'Seeking information and deciding on food changes' and 'Monitoring food changes'. Additional sub-themes described who led food changes, women's filtering of information, and moderation or 'treats'. Throughout these food change journeys interactions between men and women were at play, demonstrating how gender relations and dynamics acted to shape couples food negotiations and men's food practices. Findings reveal that attention to gender relations and the men's family food dynamics should inform diet interventions for men with prostate cancer in order to improve uptake

The Effect of Bacterial Infection on the Biomechanical Properties of Biological Mesh in a Rat Model

BACKGROUND: The use of biologic mesh to repair abdominal wall defects in contaminated surgical fields is becoming the standard of practice. However, failure rates and infections of these materials persist clinically. The purpose of this study was to determine the mechanical properties of biologic mesh in response to a bacterial encounter. METHODS: A rat model of Staphylococcus aureus colonization and infection of subcutaneously implanted biologic mesh was used. Samples of biologic meshes (acellular human dermis (ADM) and porcine small intestine submucosa (SIS)) were inoculated with various concentrations of methicillin-resistant Staphylococcus aureus [10(5), 10(9) colony-forming units] or saline (control) prior to wound closure (n = 6 per group). After 10 or 20 days, meshes were explanted, and cultured for bacteria. Histological changes and bacterial recovery together with biomechanical properties were assessed. Data were compared using a 1-way ANOVA or a Mann-Whitney test, with p<0.05. RESULTS: The overall rate of staphylococcal mesh colonization was 81% and was comparable in the ADM and SIS groups. Initially (day 0) both biologic meshes had similar biomechanical properties. However after implantation, the SIS control material was significantly weaker than ADM at 20 days (p = 0.03), but their corresponding modulus of elasticity were similar at this time point (p>0.05). After inoculation with MRSA, a time, dose and material dependent decrease in the ultimate tensile strength and modulus of elasticity of SIS and ADM were noted compared to control values. CONCLUSION: The biomechanical properties of biologic mesh significantly decline after colonization with MRSA. Surgeons selecting a repair material should be aware of its biomechanical fate relative to other biologic materials when placed in a contaminated environment

Mechanical Strain Stabilizes Reconstituted Collagen Fibrils against Enzymatic Degradation by Mammalian Collagenase Matrix Metalloproteinase 8 (MMP-8)

Collagen, a triple-helical, self-organizing protein, is the predominant structural protein in mammals. It is found in bone, ligament, tendon, cartilage, intervertebral disc, skin, blood vessel, and cornea. We have recently postulated that fibrillar collagens (and their complementary enzymes) comprise the basis of a smart structural system which appears to support the retention of molecules in fibrils which are under tensile mechanical strain. The theory suggests that the mechanisms which drive the preferential accumulation of collagen in loaded tissue operate at the molecular level and are not solely cell-driven. The concept reduces control of matrix morphology to an interaction between molecules and the most relevant, physical, and persistent signal: mechanical strain.The investigation was carried out in an environmentally-controlled microbioreactor in which reconstituted type I collagen micronetworks were gently strained between micropipettes. The strained micronetworks were exposed to active matrix metalloproteinase 8 (MMP-8) and relative degradation rates for loaded and unloaded fibrils were tracked simultaneously using label-free differential interference contrast (DIC) imaging. It was found that applied tensile mechanical strain significantly increased degradation time of loaded fibrils compared to unloaded, paired controls. In many cases, strained fibrils were detectable long after unstrained fibrils were degraded.In this investigation we demonstrate for the first time that applied mechanical strain preferentially preserves collagen fibrils in the presence of a physiologically-important mammalian enzyme: MMP-8. These results have the potential to contribute to our understanding of many collagen matrix phenomena including development, adaptation, remodeling and disease. Additionally, tissue engineering could benefit from the ability to sculpt desired structures from physiologically compatible and mutable collagen